Are they some graphic card benchmark for linux environment ? From my windows experience, drivers are important, and often underestimate. My linux gaming experience is very bad, lots of my game are unstable, and others use a lot more resources than with windows. However, when I ask people, some of them have no issue at all, even with a similar environment (Debian + Steam). I may consider buy specific graphic card to stay on linux, but I couldn't find any clue to know which one are more adapted.
Thx for your leads !
Go AMD. The open-source drivers already provide the best performance compared to the closed-source ones, and are included in the kernel and Mesa, which means the cards will work out of the box. For the best performance and latest drivers and optimizations you should switch to a distro with more up to date packages than Debian if you plan on buying a current gen card tho. For example, Fedora is a very good mix between working OOTB, ease of use and bleeding-edge packages.
nVidia is... difficult. The open-source drivers are getting better but are still way behind closed-source drivers, and each closed-source drivers version only works with a single kernel version. It might work OK as long as the drivers and kernel are kept in sync (I think Pop! or Nobara have nVidia specific versions for this reason), but otherwise each kernel upgrade is a risk. Plus nVidia drivers are basically shit with Wayland and cause a ton of issues.
Intel has a good track record with iGPUs so discrete cards should be as trivial to use as AMD ones, if more at the entry-level performance-wise.
+1 for AMD, but...
This is misleading. OP may have chosen Debian for a reason, as most Debian users do, and they don't have to give it up just because they're gaming.
Even with Debian Stable and a very recent AMD card, they would just have to grab a newer kernel (the easiest would be from Stable Backports) and maybe new amdgpu firmware (from here). Everything else would be covered by the Steam runtime (or Flatpak, if they use that). It's not all that difficult. Performance is comparable to other distros.
Source: I game on Debian Stable with a recent AMD card.
Second for AMD. Team Red is bringing it right now anyway, the only card that doesn't have an AMD equivalent is the 4090, anything else you can get an AMD equivalent for basically half the price. I run the 7900XTX and I can't find anything that stalls this card.
Caveats, if you want to do AI/ML stuff, NVidia is the way to go. Ray tracing is also about a generation behind, but it's not really noticeable to me. Instead of 4000 series ray tracing you get 3000 series ray tracing (roughly). Even with those caveats, it's the best card I've ever owned.