When you attempt to reboot you will have a non-working system (hope you have physical access to the box - yuk)
the following output I think deserves attention:
DKMS: install completed.
update-initramfs: Generating /boot/initrd.img-5.8.0-59-generic
W: Possible missing firmware /lib/firmware/amdgpu/vangogh_gpu_info.bin for module amdgpu
W: Possible missing firmware /lib/firmware/amdgpu/navi10_mes.bin for module amdgpu
3 options I see here
A: Investigate why navi10_mes and vangogh_gpu_info are missing and if that is related to boot crash B: Go without AMDGPU-PRO C: stick with amdgpu-pro-20.40-1147286-ubuntu-20.04 and once again roll back to 5.4.0-58-generic headers
Please fix amdgpu-pro-21.20 to work on Ubuntu, test it on a physical box, reboot, use darktable-cltest or any GPU test, confirm working, ect... I feel this is a reasonable expectation and request. Please advise? thoughts? comments?
PS: thank you for making a mostly good product. Been using amdgpu-pro since version amdgpu-pro-17.40-492261 up until amdgpu-pro-20.45... all was well! Cheers.