You can run darktable-cltest on you Linux, too (not in the FlatPak).
I use NVidia, so I don’t follow what drivers one needs for AMD. It used to be the case that (a part of) the proprietary driver was needed, but then I heard rustic got improved a lot. I’m sure fellow AMD users will be able to help. But maybe you’ll need rocm? See
How to make my AMD GPU work with the Flatpak version of darktable? - #8 by tankist02 and
Opencl Rx580 Linux Mint 21.3 amdgpu - #11 by tankist02