Krita is exceptional (and it's FOSS):
https://krita.org/
It's targeted at drawing more than image editing (though Krita handles both raster and vector in one document), but more than any other graphics application, they make relatively advanced features[1] discoverable and usable. And being FOSS, it's extensible and has an apparently active community.
Really a gem of usability among FOSS applications. After I tried it, I was surprised I hadn't heard about it. The best graphics program I've ever used, especially in respect to UI (for context, I never really dug into Photoshop and I now despise other Adobe interfaces I am forced to use). Great documentation too: clear, succinct, detailed, easy to find what you need. I rarely use graphics applications, and I didn't need to post one question, and maybe looked once or twice beyond the documentation.
And being FOSS, no dark patterns to worry about at all! I find FOSS to be a relief these days - I hardly have to worry about tracking or the rest of that nonsense.
[1] Advanced for an IT techie - I don't know what a graphic designer or artist would say, though they are the target audience.