I doubt up to date GIMP has many more features than Photoshop CS2 which was a pay once license :)
edit: Ha, Adobe still has the download link for free Photoshop CS2 live. Apparently it works in Wine, too.
For anyone who is wondering, Photoshop CS2 works well on Wine stable on Linux. I'm going to be honest, CS2 and GIMP are pretty similar feature wise.
But won't work on ARM, so it wouldn't work on Raspberry Pi 4. If Apple starts a wave with its much-suggested move to ARM, CS2 will not survive but GIMP likely will.