I am currently running windows with my AMD, but that is only because I prefer windows. Pretty much nothing, except Stable Diffusion at very slow speeds via direct ml and koboldcpp-rocm inference, works. I was able to use normal Stable Diffusion on Ubuntu after ~2h of trying to get it to work. Sadly, it randomly stopped working the next week. Never managed to get Ooba working, but I gave up rather quick after I found koboldcpp-rocm.
You can find a n-gpu-layers slider, when you select llama.cpp. You can just input the max amount if you want everything on the GPU. Otherwise the model you loaded will say how many layers it has during loading in the terminal.