AMD no doubt. Back in 2017 AMD had recently open sourced their drivers I was in the market for a GPU, but you know the saying "fool me once shame on you", AMD used to SUCK on Linux, people always seem to forget about it, so I chose an Nvidia. I don't regret my choice, but over the years AMD proved that it had really changed, so my new GPU now is an AMD, and the experience is just so much better.

Today it might be a turning point, maybe Nvidia will change, maybe they'll change their mind and fuck It up, they've done it in the past, so I wouldn't buy an Nvidia just in case they do the right thing for once, AMD is already doing the right thing for years. Also if you go with Nvidia forget about Wayland, and every day more and more distros are going Wayland only, so if you go Nvidia you might find yourself holding a very expensive paperweight in a few years.