Just updated linux kernel to 5.9 as I’m using the testing repo.
In this machine there is Intel and Radeon graphics. The radeon kernel module didn’t cause problems with kernel 5.8 series. But with kernel 5.9 the picture is very distorted at boot.
Blacklisting the radeon kernel module “fixed” it, and now I’m on Intel graphics.
So, I again recommend having also the LTS kernel (or another officially supported kernel), just in case.