This is the setup I use in debian, it might give you a hint (no PPAs, standard repos):
sudo apt install mesa-vulkan-drivers mesa-vulkan-drivers:i386 libvulkan1 libvulkan1:i386 vulkan-tools vkd3d-demos mesa-opencl-icd clinfo libxrandr2 libxrandr2:i386 libvulkan-dev libvulkan-dev:i386 libgl1-mesa-dri libgl1-mesa-dri:i386 vkmark glmark2-x11 firmware-amd-graphics radeontop xserver-xorg-video-amdgpu
You need to activate contrib, non-free, non-free-firmware repos:
sudo nano /etc/apt/sources.listYou should have something likedeb http://URL_OF_THE_REPO DISTRIBUTION main, you need to addcontrib non-free non-free-firmwareto the end of those lines like:deb http://URL_OF_THE_REPO DISTRIBUTION main contrib non-free non-free-firmwarethen you dosudo apt updateand try installing the packages again.