You could add a reply there with your version of Qubes and any other info so the devs become aware that this is not just happening to one person.
Oh and in the meantime you can still update dom0 by using the following command (I’m assuming you’re running Qubes 4.1.x): sudo qubes-dom0-update --clean --console --show-output --releasever=4.1
the same happened to me. installed vanilla new template for debian-12 and changed everything to it, then deleted debian-11. dom0 updates fails just like reported. all other qubes update OK.
reinstalled debian-11 templates, create new disposable debian-11-dvm for firewall qube and switched sys-net(debian-11) and sys-firewall(debian-11-dvm) to it.
this time the GUI updated dom0 just fine (no packages to install but didn’t throw lots of error messages).
I can report the same. Once I set sys-net-wifi and sys-firewall-wifi to be based off debian-11 it worked fine. (Most people should ignore the -wifi suffixes; I have different networking for the two networks I am connected to, to keep them separated.)
In theory setting dom0 up to update through whonix is also an option. That does function and would allow me to abandon debian 11 altogether, but then I could not update the whonix template to save my life (Can't update whonix-gw-16). Seeing that update icon ON all of the time whether or not there was something updateable that needed updating was a non-starter. (It’s like a “check engine” light that stays on even though you’ve attempted to maintain the minor thing it’s complaining about…you have no idea when a bigger, much more significant problem comes along, then.) Anyhow, if you don’t have problems updating whonix, it’s definitely an option vs. keeping debian-11 around.