resolution problems

[hubbling]

When I try to make small changes the resolution of the image gets worse - not in pixel x pixel (this stays the same), but in regarding an zooming into the image!
That is a huge problem for me.
What is wrong there???
See the pictures:

[hubbling]

I am using google pixel 8 pro + jpeg picture

[T8RIN]

You need to change image scale mode when saving i think

[hubbling]

I also tried different scale modes, but until now no luck.
Which scale mode should be preferred???

[T8RIN]

Is this after saving, or while previewing?

[hubbling]

after saving.
I also deleted the app, then reinstalled.
I did not change any setting...