I noticed that to install from Debian 13 repo you are forced to install linux-image-6.0.0-rt-amd64 and linux-image-rt-amd64 but I already have a newer kernel installed...
Should not matter much, the newer kernel will still be on the top of the list when booting.
Hold down shift button after power on to see the GRUB menu and check what is the first boot option.
