My choices on Linux for image creation and editing were limited to mostly GIMP (see my GIMP 3.0 review here) and Krita. With a bit of Photopea thrown in now and again. And over the last few months ...

Krita is one of my favorite Photoshop alternatives; it offers all I need from a creative tool, so I won’t yearn for Photoshop ...

Krita may be free, but for such a low price, it may well be worth checking out Infinity Painter. When it comes to the best drawing apps on a tablet, Procreate is the app most talk about.