I've been using GIMP since I was 9 years old mate, I've tried using Photoshop and I find it to be a nightmare, can you even get GMIC on Photoshop? It's all just a matter of what you first used.
photopea.com is pretty great and doesn't require you to install anything. Ever since I found it I never used gimp anymore. I'm only use it for light editing though (light touch up, removing background, etc), so I have no idea if it can replace photoshop for professional users.
I'd rather use Photoshop 1998 than Gimp.