@grumpygamer as a massive FOSS advocate who's used Linux as a primary O/S for 20 years, and as somebody who's built a career working with designers... I can confirm there's sadly no true Photoshop replacement, sorry. 🤷♂️
There are a lot of great tools out there, and I personally do find Gimp (please don't block me 😆) more intuitive for many things, but Adobe are masters of adding regular changes to a proprietary file format and making other tools' importers look terrible. They've won the market.