That's not exactly my impression from following the design conversations through the years. They're more approaching decisions from the angle of what they think is best, their philosophy is to plainly ignore what others do and follow their own direction. Of course taking inspiration from Photoshop might sometimes be a good thing, if it doesn't conflict with the GIMP way of doing things.
I've noticed in recent years some newcomer devs have had discussions on how to design their contributions, mentioning Photoshop and other alternative ways and there were just conversations about the merits of the different approaches that could be taken and what would fit the GIMP best, without bias.
Anyway, I wasn't aware that GIMP UX suffers, I've never used anything else and am happy with it. It seem logical to me, obviously with fewer features than Photoshop but how much can a couple of guys do and they've had to refactor most of the GIMP for 3.0, but that'll open up for a lot of functionality being added moving forward..
Yeah they don't hate Linux, they just have their own priorities. That said I'm running Nvidia+Wayland happily, for desktop they have worked a lot more on Wayland this year, the upcoming driver fixes a bunch of things, and my distrib handled driver installation and updates, I never have to think about it.