These days, virt-install seems to require:

--os-variant=XYZ

e.g.

--os-variant=rhel10.0

If said parameter isn't provided it will cause the following error message to appear and the installation stops immediately:

Starting install...
ERROR    Couldn't find kernel for install tree.
Domain installation does not appear to have been successful.
If it was, you can restart your domain by running:
  virsh --connect qemu:///system start RHEL10-Test-VM
otherwise, please restart your installation.

There are at least two Bugzilla entries for Fedora for this and four pages of Google hits when searching for this particular error message. Unfortunately, a lot of the suggested solutions there are wrong. So I think this might perhaps be a good opportunity for an article in the RH knowledge base. I couldn't find one.

This is obviously a very minor inconvenience, but I thought I might still create a Jira issue just in case anyway.