AMD drivers are now open and in the mainline kernel. They dropped their proprietary driver and now use the upstream MESA stack. Nvidia also still suffers from a 20-30% performance drop on DX12 games on Linux, while AMD does not.
It used to be the reverse as you stated, but that hasn't been true since about 2015.
Okay, but AMD isn't accelerated. It's godawful slow for anything to do with video, and really you just need an NVidia card if you're doing anything to do with video editing or motion graphics.
The built-in amdgpu drivers are awful, constantly crashy and with very poor hardware support of anything more than a couple of years old.
It doesn't have CUDA beacuse that's NVidia-only and it doesn't have OpenCL unless you use the binary-only drivers, which only work on a handful of very new cards.
I actually switched from a 7900 XTX to a 4090 BITD because I wanted CUDA, so I get that angle, but that doesn't mean I go around telling people "AMD isn't accelerated," because it's not true and it's a silly thing to try to claim.
NVIDIA is currently improving as well! Of course AMD is still the safer bet, but I think things look bright for NVIDIA in the future. The kernel driver was open sourced, and they are currently working on the DX12 performance issues.
Then you'll have AMD headaches. NVidia is the only accelerated graphics card fully supported on Linux.
You only get acceleration in AMD if you use their binary-only drivers and they only support cards for about a year.