You need to install a kernel 5.10+ and amd firmware files to get support for the ryzen 5xxx gpu, otherwise the nvidia gpu won’t work either:
You will need 4 packages
linux-headers-XX
linux-headers-XX-generic
linux-image-unsigned-XX-generic
linux-modules-XX-generic
from Index of /~kernel-ppa/mainline/v5.11.14
and copy all files green_sardine* from https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/amdgpu to /lib/firmware
Then add the graphics drivers ppa and install the nvidia driver using Software&Updates application.