Nvidia isnt so bad if you're on a stable distro it supports and using x(though Ive heard wayland support is improving for it). On rolling or more cutting edge distros where the kernel is likely to change every few weeks and major DE versions might ship that proprietary driver will hurt.
That said while amd is generally better on linux for this reason it's worth mentioning that it has two huge flaws:
1.Its not perfect like the fans mention. As someone who owned a 3500u and 6650u apu life under amd isnt always sunny. 3500u had a kernel regression for about half a year that prevented the cpu from idling and rembrant apus have an issue where the whole system locks up which seems to come and go(feels like it's gone for now but Ive thought that before). Desktop gpus are better, but they still did suffer from driver bugs. I think my experience with my 5600xt was better than windows fans had for that generation, but it was not entirely stable and I did suffer from many kernel panics and system freezes. A few mesa and kernel releases fixed that, but it wasnt perfectly smooth. In addition to that no hdmi 2.1 support which is fine unless you game using your nice oled tv because no tvs come with display port. Proprietary drivers do allow for supporting some of the more obnoxious features that arent allowed.
- It can vary gpu/cpu to gpu/cpu for how fresh your software will need to be, but generally newer hardware needs very new kernels just for basic support and it may need a few more releases to get stable or good. So if you want to just sit back with ubutnu LTS or debian you need to make sure the release cycle lines up with support for your hardware. The other end of the spectrum is that being on a bleeding or cutting edge distro can mean stability issues and regressions. So for example a month or three ago fedora pushed a kernel update that had a regression where my 6800xt gpu wouldnt clock up when utilized so gaming framerates tanked and retroarch shaders were choking up. I could just use the old kernel but I had to make sure that the kernel updates didnt bump it away. Also an entire point release and several releases after that before the bug was fixed.
So while there is a lot of pro amd comments in the linux world and its worth acknowledging that the open source drivers are generally good it's not perfect and the grass isnt always greener.