Despite what people say, Nvidia is certanly the one with most complete support for Linux... if support for a OS is defined by how Windows is supported.

The way GPU are supported on Windows is this: Microsoft pick your whole experience, then you install the setup.exe with a bunch of bloat and some advertisement from the OEM (Nvidia or the Nvidia's GPU resellers like EVGA, ASUS...)

If you stick with the most popular distro which have the exact Linux kernel Nvidia support... yeah, nothing can beat Nvidia. You have amazing support for nearly every feature your GPU offer (cuda, ray tracing etc), but if you want to try some kind more exotic flavour of Linux, expect problem.

AMD, being much more OpenSource friendly, it mean you can have the top notch 3D acceleration on basically anything, even Puppy Linux ( a ~200MiB Linux live distro), but if you're looking for more advanced features (like OpenCL of LLM support)... well, good luck with that: eventually, someday, they also will work (if meanwhile AMD don't drop support your card if too old).

There's no perfect answer. Despite the flaws, people in the Linux community love AMD because they give drive support in the "Linux's way". Nvidia support is better, but it's the "Window's way", and you need to stick to the rules on what Nvidia consider "Linux" (which, for short, is "Canonical's Ubuntu")