I'm a happy user of GIMP whe also happened to have switched from Photoshop. I even managed to use keyboard shortcuts cuz it's so intuitive. I never make efforts to learn them, not in gimp not elsewhere, but the description was straightforward that I would have a hard time not learning it. (P for paint/pen, M for move, T for text, Shift+E for erasor)

Now I like Krita too, but mostly because of the pen library. Krita is actually less intuitive than GIMP imo (Why are there different moving tools for vector and raster layers? How do I enlarge my selection? How do I flip the canvas for correction reasons? I know there's a shortcut for that, I pressed it by accident.)

Would I call Krita bad UX? Not really, it has a place in my workflow. But I prefer GIMP for its power and since I can get around it well. They have been obviously stretched thin for a long time, I myself have been waiting for features and improvements in GIMP for years. But really, I think people underestimate the complexity of these tools and quick to label them unintuitive. I don't think you can overhaul the UI without removing some or many features GIMP currently has.