A regression - something got removed. 
Yes. You can remove the 5.11 kernel completely
sudo apt remove linux-headers-5.11.0-38-generic linux-modules-5.11.0-38-generic linux-modules-extra-5.11.0-38-generic linux-image-5.11.0-38-generic
Once done, open Synaptic (if you do not have it, sudo apt install synaptic)
Then click the search button.
Search for:
5.8.0-63
Tick all the boxes on the ones that You Have Installed.
Now go to the menubar and select Package and move down to Lock Version and select it to Lock the kernel to its current version.
That will prevent it from Upgrading to the newer non-working kernel.