I installed the Nvidia 555 proprietary drivers (which support Wayland) on Debian Trixie with the .sh installer from nvidia.com and when I try to login with Wayland, I do not get the option; the cog on the login screen does not show with Xorg which indicates that it only supports logging in with Xorg and Wayland is disabled, and of course when I login $XDG_SESSION_TYPE does not have the wayland value.
I tried setting WaylandEnable=true in /etc/gdm3/daemon.conf (aka /etc/gdm3/custom.conf for Ubuntu users) but that had no effect.
I know that GDM is wrong and I can use Wayland, but GDM refuses to let me use it.
Edit: $ sudo cat /sys/module/nvidia_drm/parameters/modeset returns Y (in case you thought that was the problem)