Hello there, you can start to try with this work GitHub - X547/RadeonGfx from @X512 that driver seems to work only in their own amdgpu, but you can try to compile and test it to give some live on the project i suppose.
You have this threads too Vulkan lavapipe software rendering is working on Haiku
I was trying to compile the RadeonGFX Build.sh from X547 and got to compiling libdrm2 and the compiler quit with an error…
failed: amdgpu/libdrm_amdgpu.so.1.0.0.p/amdgpu_asic_id.c.o cc -Iamdgpu/libdrm_amdgpu.so.1.0.0.p -Iamdgpu -I…/amdgpu -Iheaders -I…/headers -I/boot/home/brg/install/develop/headers/accelerant -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -O0 -g -include amdgpu/config.h -fPIC -Wsign-compare -Werror=undef -Werror=implicit-function-declaration -Wpointer-a…
If you can compile it and it works for you, please, share the results here for us.