Finished my part, ready for review.

src/main/java/com/rae/creatingspace/api/gui/elements/InputBoxWidget.java

@@ -70,8 +70,8 @@ public void setResponder(Consumer<String> stringConsumer){
     }
 
     @Override
-    public void render(@NotNull GuiGraphics graphics, int mouseX, int mouseY, float partialTicks) {
-        super.render(graphics, mouseX, mouseY, partialTicks);
+    protected void renderWidget(@NotNull GuiGraphics graphics, int mouseX, int mouseY, float partialTicks) {
+        super.renderWidget(graphics, mouseX, mouseY, partialTicks);
         //editBox.render(ms,mouseX,mouseY,partialTicks);
     }
 

src/main/java/com/rae/creatingspace/api/gui/elements/Orbit.java

@@ -81,7 +81,7 @@ public boolean isMouseOver(double mouseX, double mouseY) {
     }
 
     @Override
-    public void render(@NotNull GuiGraphics ms, int mouseX, int mouseY, float partialTicks) {
+    protected void renderWidget(@NotNull GuiGraphics ms, int mouseX, int mouseY, float partialTicks) {
         if (visible) {
             isHovered = isMouseOver(mouseX, mouseY);
             beforeRender(ms, mouseX, mouseY, partialTicks);

src/main/java/com/rae/creatingspace/api/gui/elements/SliderWidget.java

@@ -53,7 +53,7 @@ public void setMax(int max) {
         this.max = max;
     }
     @Override
-    public void render(@NotNull GuiGraphics graphics, int mouseX, int mouseY, float partialTicks) {
+    protected void renderWidget(@NotNull GuiGraphics graphics, int mouseX, int mouseY, float partialTicks) {
         if (visible){
             lerpedValue.tickChaser();
 

src/main/java/com/rae/creatingspace/content/life_support/spacesuit/OxygenBacktankBlock.java

@@ -1,12 +1,14 @@
 package com.rae.creatingspace.content.life_support.spacesuit;
 
 import com.mojang.serialization.MapCodec;
+import com.rae.creatingspace.init.DataComponentsInit;
 import com.rae.creatingspace.init.graphics.ShapesInit;
 import com.rae.creatingspace.init.ingameobject.BlockEntityInit;
 import com.simibubi.create.AllEnchantments;
 import com.simibubi.create.foundation.block.IBE;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
+import net.minecraft.core.component.DataComponentPatch;
 import net.minecraft.core.component.DataComponents;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.ListTag;
@@ -27,13 +29,16 @@
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.HorizontalDirectionalBlock;
 import net.minecraft.world.level.block.SimpleWaterloggedBlock;
+import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntityType;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.block.state.StateDefinition.Builder;
 import net.minecraft.world.level.block.state.properties.BlockStateProperties;
 import net.minecraft.world.level.material.FluidState;
 import net.minecraft.world.level.material.Fluids;
 import net.minecraft.world.level.pathfinder.PathComputationType;
+import net.minecraft.world.level.storage.loot.LootParams;
+import net.minecraft.world.level.storage.loot.parameters.LootContextParams;
 import net.minecraft.world.phys.BlockHitResult;
 import net.minecraft.world.phys.HitResult;
 import net.minecraft.world.phys.shapes.CollisionContext;
@@ -42,6 +47,7 @@
 import org.jetbrains.annotations.Nullable;
 import org.lwjgl.system.NonnullDefault;
 
+import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 @NonnullDefault
@@ -111,12 +117,8 @@ public void setPlacedBy(Level worldIn, BlockPos pos, BlockState state, @Nullable
 		if (worldIn.isClientSide)
 			return;
 		withBlockEntityDo(worldIn, pos, be -> {
-			//
 			be.setCapacityEnchantLevel(stack.getEnchantmentLevel(worldIn.holderOrThrow(AllEnchantments.CAPACITY)));
-			be.setOxygenLevel((int) stack.getOrCreateTag()//TODO implement a DataComponent for Oxygen Level in DataComponentInit
-				.getFloat("Oxygen"));
-			if (stack.isEnchanted())
-				be.setEnchantmentTag(stack.getEnchantmentTags());//TODO look at BacktankBlock
+			be.setOxygenLevel(stack.getOrDefault(DataComponentsInit.OXYGEN_LEVEL, 0));
 			if (stack.has(DataComponents.CUSTOM_NAME))
 				be.setCustomName(stack.getHoverName());
 		});
@@ -151,25 +153,15 @@ public ItemStack getCloneItemStack(BlockState state, HitResult target, LevelRead
 			item = placeable.getActualItem();
 		}
 
-		ItemStack stack = new ItemStack(item);
 		Optional<OxygenBacktankBlockEntity> blockEntityOptional = getBlockEntityOptional(level, pos);
 
+		DataComponentPatch components = blockEntityOptional.map(OxygenBacktankBlockEntity::getComponentPatch)
+				.orElse(DataComponentPatch.EMPTY);
 		int air = blockEntityOptional.map(OxygenBacktankBlockEntity::getOxygenLevel)
                 .orElse(0);
-		CompoundTag tag = stack.getOrCreateTag(); //TODO DataComponent
-		tag.putFloat("Oxygen", air);
-		tag.putFloat("prevOxygen",air);
-
-		ListTag enchants = blockEntityOptional.map(OxygenBacktankBlockEntity::getEnchantmentTag)
-			.orElse(new ListTag());
-		if (!enchants.isEmpty()) {
-			ListTag enchantmentTagList = stack.getEnchantmentTags(); //TODO look at BacktankBlock
-			enchantmentTagList.addAll(enchants);
-			tag.put("Enchantments", enchantmentTagList);
-		}
-
-        blockEntityOptional.map(OxygenBacktankBlockEntity::getCustomName).ifPresent(stack::setHoverName); //TODO look at BacktankBlock
-        return stack;
+		ItemStack stack = new ItemStack(item.builtInRegistryHolder(), 1, components);
+		stack.set(DataComponentsInit.OXYGEN_LEVEL, air);
+		return stack;
 	}
 
 	@Override
@@ -193,4 +185,26 @@ public boolean isPathfindable(BlockState state, PathComputationType type) {
 		return false;
 	}
 
+	@Override
+	public List<ItemStack> getDrops(BlockState pState, LootParams.Builder pBuilder) {
+		List<ItemStack> lootDrops = super.getDrops(pState, pBuilder);
+
+		BlockEntity blockEntity = pBuilder.getOptionalParameter(LootContextParams.BLOCK_ENTITY);
+		if (!(blockEntity instanceof OxygenBacktankBlockEntity bbe))
+			return lootDrops;
+
+		DataComponentPatch components = bbe.getComponentPatch()
+				.forget(c -> c.equals(DataComponentsInit.OXYGEN_LEVEL));
+		if (components.isEmpty())
+			return lootDrops;
+
+		return lootDrops.stream()
+				.peek(stack -> {
+					if (stack.getItem() instanceof OxygenBacktankItem)
+						stack.applyComponents(components);
+				})
+				.toList();
+	}
+
+
 }

src/main/java/com/rae/creatingspace/content/life_support/spacesuit/OxygenBacktankBlockEntity.java

@@ -13,6 +13,7 @@
 import net.minecraft.core.Direction;
 import net.minecraft.core.Direction.Axis;
 import net.minecraft.core.HolderLookup;
+import net.minecraft.core.component.DataComponentPatch;
 import net.minecraft.core.particles.ParticleTypes;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.ListTag;
@@ -41,8 +42,9 @@ public class OxygenBacktankBlockEntity extends SmartBlockEntity implements Namea
 	private Component customName;
 	private int capacityEnchantLevel;
 	private ListTag enchantmentTag;
+	private DataComponentPatch componentPatch;
 
-	private final FluidTank OXYGEN_TANK = new FluidTank(1000){
+	private final FluidTank OXYGEN_TANK = new FluidTank(1000) {
 		@Override
 		protected void onContentsChanged() {
 
@@ -65,8 +67,8 @@ public static void registerCapabilities(RegisterCapabilitiesEvent event) {
 		event.registerBlockEntity(
 				Capabilities.FluidHandler.BLOCK,
 				BlockEntityInit.OXYGEN_BACKTANK.get(),
-				(be, context)-> {
-					if (context == Direction.DOWN){
+				(be, context) -> {
+					if (context == Direction.DOWN) {
 						return be.OXYGEN_TANK;
 					}
 					return null;
@@ -114,23 +116,29 @@ public int getComparatorOutput() {
 	}
 	//TODO add DataComponent and remove prevOxygen + timer (I'm not sure we are using it)
 
+	public void setComponentPatch(DataComponentPatch componentPatch) {
+		this.componentPatch = componentPatch;
+	}
 
+	public DataComponentPatch getComponentPatch() {
+		return componentPatch;
+	}
 
 	@Override
-	protected void write(CompoundTag compound,HolderLookup.Provider registries, boolean clientPacket) {
-		super.write(compound,registries, clientPacket);
+	protected void write(CompoundTag compound, HolderLookup.Provider registries, boolean clientPacket) {
+		super.write(compound, registries, clientPacket);
 		compound.putInt("Oxygen", oxygenLevel);
-		compound.putInt("prevOxygen",prevOxygenLevel);
+		compound.putInt("prevOxygen", prevOxygenLevel);
 		compound.putInt("Timer", oxygenLevelTimer);
 		compound.putInt("CapacityEnchantment", capacityEnchantLevel);
 		if (this.customName != null)
-			compound.putString("CustomName", Component.Serializer.toJson(this.customName,registries));
+			compound.putString("CustomName", Component.Serializer.toJson(this.customName, registries));
 		compound.put("Enchantments", enchantmentTag);
 	}
 
 	@Override
-	protected void read(CompoundTag compound,HolderLookup.Provider registries, boolean clientPacket) {
-		super.read(compound,registries, clientPacket);
+	protected void read(CompoundTag compound, HolderLookup.Provider registries, boolean clientPacket) {
+		super.read(compound, registries, clientPacket);
 		int prev = oxygenLevel;
 		capacityEnchantLevel = compound.getInt("CapacityEnchantment");
 		OXYGEN_TANK.setCapacity(OxygenBacktankUtil.maxOxygen(capacityEnchantLevel));
@@ -151,7 +159,7 @@ protected void playFilledEffect() {
 		for (int i = 0; i < 360; i += 10) {
 			Vec3 m = VecHelper.rotate(baseMotion, i, Axis.Y);
 			Vec3 v = baseVec.add(m.normalize()
-				.scale(.25f));
+					.scale(.25f));
 
 			level.addParticle(ParticleTypes.SPIT, v.x, v.y, v.z, m.x, m.y, m.z);
 		}
@@ -160,7 +168,7 @@ protected void playFilledEffect() {
 	@Override
 	public Component getName() {
 		return this.customName != null ? this.customName
-			: defaultName;
+				: defaultName;
 	}
 
 	public int getOxygenLevel() {
@@ -169,7 +177,7 @@ public int getOxygenLevel() {
 
 	public void setOxygenLevel(int oxygenLevel) {
 		this.oxygenLevel = oxygenLevel;
-		OXYGEN_TANK.setFluid(new FluidStack(FluidInit.LIQUID_OXYGEN.get(),oxygenLevel));
+		OXYGEN_TANK.setFluid(new FluidStack(FluidInit.LIQUID_OXYGEN.get(), oxygenLevel));
 		setChanged();
 		sendData();
 	}
@@ -195,4 +203,4 @@ public void setCapacityEnchantLevel(int capacityEnchantLevel) {
 		this.OXYGEN_TANK.setCapacity(OxygenBacktankUtil.maxOxygen(capacityEnchantLevel));
 	}
 
-}
+}

src/main/java/com/rae/creatingspace/content/life_support/spacesuit/OxygenBacktankItem.java

@@ -1,5 +1,6 @@
 package com.rae.creatingspace.content.life_support.spacesuit;
 
+import com.rae.creatingspace.init.DataComponentsInit;
 import com.simibubi.create.foundation.item.LayeredArmorItem;
 import net.minecraft.core.Holder;
 import net.minecraft.nbt.CompoundTag;
@@ -29,20 +30,6 @@ public OxygenBacktankItem(Holder<ArmorMaterial> material, Properties properties,
         this.blockItem = placeable;
     }
 
-    @Override
-    public void inventoryTick(ItemStack backtank, Level level, Entity entity, int nbr, boolean isMoving) {
-        CompoundTag tag = backtank.getOrCreateTag();//TODO data component + remove the prev oxygenLevel and toUpdate as we don't need it.
-
-        float o2amount = tag.getFloat("Oxygen");
-        float prevO2amount = tag.getFloat("prevOxygen");
-        boolean toUpdate = tag.getBoolean("toUpdate");
-        if (toUpdate) {
-            tag.putFloat("prevOxygen",o2amount);
-            tag.putBoolean("toUpdate", false);
-        }
-        // may be ? -> in the ticking entity logic make the server update the itemstack -> here don't now what is before and after
-    }
-
     @Nullable
     public static OxygenBacktankItem getWornBy(Entity entity) {
         if (!(entity instanceof LivingEntity livingEntity)) {
@@ -60,7 +47,6 @@ public static OxygenBacktankItem getWornBy(Entity entity) {
                 .useOn(ctx);
     }
 
-    @Override
     public boolean canBeDepleted() {
         return false;
     }
@@ -89,9 +75,8 @@ public Block getBlock() {
         return blockItem.get().getBlock();
     }
 
-    public static float getRemainingAir(ItemStack stack) {
-        CompoundTag orCreateTag = stack.getOrCreateTag();//TODO DataComponent
-        return orCreateTag.getFloat("Oxygen");
+    public static int getRemainingAir(ItemStack stack) {
+        return stack.getOrDefault(DataComponentsInit.OXYGEN_LEVEL, 0);
     }
 
     public static class O2BacktankBlockItem extends BlockItem {

src/main/java/com/rae/creatingspace/content/life_support/spacesuit/OxygenBacktankUtil.java

@@ -1,5 +1,6 @@
 package com.rae.creatingspace.content.life_support.spacesuit;
 
+import com.rae.creatingspace.init.DataComponentsInit;
 import com.rae.creatingspace.init.TagsInit;
 import com.simibubi.create.AllEnchantments;
 import com.simibubi.create.AllSoundEvents;
@@ -62,19 +63,15 @@ public static boolean hasOxygenRemaining(ItemStack backtank) {
 		return getOxygen(backtank) > 0;
 	}
 
-	public static float getOxygen(ItemStack backtank) {
-		CompoundTag tag = backtank.getOrCreateTag();//TODO DataComponent
-		return Math.min(tag.getFloat("Oxygen"), maxOxygen(backtank));
+	public static int getOxygen(ItemStack backtank) {
+		return Math.min(backtank.getOrDefault(DataComponentsInit.OXYGEN_LEVEL, 0), maxOxygen(backtank));
 	}
 
 	public static void consumeOxygen(LivingEntity entity, ItemStack backtank, int i) {
-		CompoundTag tag = backtank.getOrCreateTag();
 		int maxOxygen = maxOxygen(backtank);
-		float oxygen = getOxygen(backtank);
-		float newOxygen = Math.max(oxygen - i, 0);
-		tag.putFloat("Oxygen", Math.min(newOxygen, maxOxygen));
-		tag.putBoolean("toUpdate",true);
-		backtank.setTag(tag);
+		int oxygen = getOxygen(backtank);
+		int newOxygen = Math.max(oxygen - i, 0);
+		backtank.set(DataComponentsInit.OXYGEN_LEVEL, Math.min(newOxygen, maxOxygen));
 
 		if (!(entity instanceof ServerPlayer player))
 			return;

src/main/java/com/rae/creatingspace/content/life_support/spacesuit/RemainingO2Overlay.java

@@ -2,11 +2,13 @@
 
 import com.rae.creatingspace.api.gui.elements.SliderWidget;
 import com.rae.creatingspace.configs.CSConfigs;
+import com.rae.creatingspace.init.DataComponentsInit;
 import net.minecraft.client.DeltaTracker;
 import net.minecraft.client.Minecraft;
 import net.minecraft.client.gui.GuiGraphics;
 import net.minecraft.client.gui.LayeredDraw;
 import net.minecraft.client.player.LocalPlayer;
+import net.minecraft.core.component.DataComponents;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.world.entity.EquipmentSlot;
 import net.minecraft.world.item.ItemStack;
@@ -35,9 +37,7 @@ public void render(GuiGraphics graphics, DeltaTracker deltaTracker) {
         ItemStack itemInChestSlot = player.getItemBySlot(EquipmentSlot.CHEST);
 
         if (itemInChestSlot.getItem() instanceof OxygenBacktankItem){
-            CompoundTag tag = itemInChestSlot.getOrCreateTag();//TODO DataComponents
-            float o2Value = tag.getFloat("Oxygen");
-
+            int o2Value = itemInChestSlot.getOrDefault(DataComponentsInit.OXYGEN_LEVEL, 0);
             gauge.setMax(OxygenBacktankUtil.maxOxygen(itemInChestSlot));
             gauge.setChase((int) o2Value);
             gauge.render(graphics, (int) mc.mouseHandler.xpos(),(int) mc.mouseHandler.ypos() ,deltaTracker.getRealtimeDeltaTicks());

src/main/java/com/rae/creatingspace/content/life_support/spacesuit/SpacesuitHelmetItem.java

@@ -114,7 +114,7 @@ public static void breatheUnderwater(EntityTickEvent.Pre event) {
 				entity.getPersistentData()
 						.putInt("VisualBacktankAir", Math.round(O2Backtanks.stream()
 								.map(OxygenBacktankUtil::getOxygen)
-								.reduce(0f, Float::sum)));
+								.reduce(0, Integer::sum)));
 
 			if (!second)
 				return;