I have been using AMD GPU (Radeon Pro W7500) on Manjaro since July, and although it is less stable than Nvidia, it generally works.
Manjaro gets rolling releases, sometimes opencl is updated, sometimes rocm, sometimes amdgpu driver; a few times it happened that one day update stopped my GPU from working, and the other update revived it back; now is the best period because since early February it is working for me nicely everyday. Maybe it was possible to get it to work after any update, but I'm too nooby. I don't like Ubuntu because it has become corpo-Linux.
I also use HSA_OVERRIDE_GFX_VERSION environmental variable, to immitate Radeon Pro W7700 :).
Sad that AMD leaves support for GPUs so fast, and for weaker GPUs does not provide support for ROCm at all out of the box, not every person has time to dig. Do You know if that variable can be used to provide ROCm for RDNA1 GPUs?
I use it for Folding at Home distributed computing project, along with Nvidia RTX 2000 Ada Generation. It is less efficient that I expected, because CUDA tasks are better than OpenCL tasks; one day HIP tasks will come and Radeon will become much better.
Isn't Your RX6750XT blocked by 8 GB of RAM? Generally it is perfect to have at least twice as much RAM as GPU RAM.