Hello @ljon. This is a topic we discuss now and then but there isn't likely to be any solution available in time to address your issue. The WMCS admins need to be able to maintain the ability to manage and configure guest VMs; to support arbitrary base images we would need to re-implement all of our existing config and remote-execution tools to work on each suported distro.

If you can convince your user/contractor/whatever to give Debian Bullseye a try, they will most likely find it to be adequate since Debian and Ubuntu are very similar. Many Ubuntu packages are just repackaged Debian builds, and it's not unusual to be able to download and install an Ubuntu .deb directly onto Debian.