I think that is the main issue. 90% games is a lot, but is not nearly enough when the most popular multiplayer titles simply do not work due to usage of anti-cheat. For example you cannot play the new Battlefield 6.
As for GIMP, while I understand it can do many things as Photoshop, it is not close in terms of features and the UX is unfortunately terrible.
While I can understand that it's frustrating. Kernel level Anticheat is a abomination in itself and should in no way be supported. It is a security flaw in itself!
It's also unfortunately impossible to have a good competitive multi-player online experience without kernel-level anti-cheat. It's simply too easy to cheat at many of these games in the absence of strict control measures, and even a single cheater can ruin a game session for every other gamer.
No one reached directly for kernel-level anti-cheat. It was the result of an escalation of the sophistication of cheating solutions.
GIMPs UX is wonderful, and Photoshop UX is poison. The problem is that after torturing yourself to learn Photoshop, and sitting in it for 8 hours a day (for many people; I worked in prepress) makes you think that it has been designed rationally rather than simply cobbled together and stuffed with ads. Illustrator, being older, is even worse.
People who work with Photoshop have never worked with any other thing. The way they learned to edit bitmaps was through Photoshop. They can't separate the act and the product in their heads. Thank god for Affinity getting into the mix.
One just has to deal with GIMP as it is, and stop trying to project Photoshop paradigms onto it. People just need to stop thinking of FOSS as the generic, off-brand or ersatz versions that pass or fail due to their degree of imitation of some other product.
IMO, every step GIMP takes towards Photoshop UI is a regression. GIMP's problems have been technical, such as color management and non-destructive editing, and they're gradually falling away.
As for GIMP, while I understand it can do many things as Photoshop, it is not close in terms of features and the UX is unfortunately terrible.