@Draekos@yiff.life I have two setups: one is laptop + ext monitor, garuda linux (arch), and the other is bazzite at home on an ultrawide. Both kde and wayland.
More just sharing my experience than offering fixes here.
On arch, opentabletdriver has been able to recognize my small usb wacom tablet, and allowed me to do configure what screen, proportions, etc in a sane way. It did not, however, work at all on bazzite (flatpak). I haven't tried yet, but maybe if I install opentabletdriver using rpm-ostree instead it'll work (Bazzite comes with flatseal so stuff gets limited access to your pc)
Without opentabletdriver, I have the same issue you described in a different reply, where I have to drag my mouse to the correct screen before using the tablet. The pressure always worked fine though.
I also have an xp-pen artist 12 but that has a linux driver so never had issues.
Krita from the bazzite bazaar or its arch repo works like a charm for me