https://bugzilla.kernel.org/show_bug.cgi?id=73291
--- Comment #9 from Mike Cloaked mike.cloaked@gmail.com --- Booting with modprobe.blacklist=radeon added to the kernel line in the rEFInd boot manager gives a successful boot to a graphical screen. So thank you, this is a workaround for the present.
I can upload the systemd journal for this boot if it is useful?