When I tried to build kali template based debian-10,I followed the doc to change the qubes sources from the buster to bullseye and enable the bullseye-testing and bullseye securitytesting.Then I add the kali sources and run “apt-get update”," apt-get remove libgcc-8-dev && apt-get install libc6-dev" as doc. However,when I run"apt dist-upgrade", it said that the qubes-* package will be removed.
I can’t help you on the specifics of your issue here. But I would advise you checking out the kali template that’s being worked on.
I can as well really recommend the Kali Template by @fepitre I am using it every other day on a Qubes 4.1 Workstation without any issues so far.