Linux Hardware

I'm thinking about getting a desktop and am looking for some advice. The machine will primarily be for photography and digital art, music production/recording and, ideally, for experimenting with local AI. I would like to use only open source firmware and drivers if possible, as well as have a discrete GPU. If I can keep cost down by buying second-hand then that is fine! I currently use Debian on my laptop and would lean towards using that on the new computer, although KXStudio looks like it could be good for the music side of things. Any advice or suggestions would be much appreciated :)