System details
Omarchy 3.3.1, Hyprland 0.53.1, Waybar 0.14.0, 2560x1440@210Hz scale 1.0
What's wrong?
The workspace buttons in waybar's style.css use margin: 0 1.5px which causes a thin visible line artifact due to fractional pixel rendering.
Fix: Change to margin: 0 2px in config/waybar/style.css
Tested on 1440p 210Hz monitor.