Experienced similar issues initially. Here’s what I did that (at least for a couple of hours now) resolved these issues:
- I copied the amdgpu folder from the mentioned firmware repo.
- I added the backports repo as documented here: Instructions
- After an
sudo apt update
I searched for a more recent Linux kernel withapt search linux-image
- I installed the latest signed image available at the time of writing:
sudo apt install linux-image-6.6.13+bpo-amd64/stable-backports
- You can ignore the “missing firmware errors” and after installation is completed, just reboot.