Hey thanks for your concern but it works after rebbot too.
I added these repos:
sudo nano /etc/apt/sources.list
deb http://deb.debian.org/debian/ bullseye main
deb-src http://deb.debian.org/debian/ bullseye main
deb http://security.debian.org/debian-security bullseye-security main contrib
deb-src http://security.debian.org/debian-security bullseye-security main contrib
deb http://deb.debian.org/debian/ bullseye-updates main contrib
deb-src http://deb.debian.org/debian/ bullseye-updates main contrib
I haven’t come across any problems in the last couple of hours I used the computer.
On the website you shared it says:
Debian Backports provides new packages with new features on supported Debian stable releases.
However I still don’t understand why you think I should choose a “backport” for the kernel.