Great to hear!
We suspected that a rpi4 would be able to run virtual machines but I don’t have any around and only tested LXD VMs on arm64 using much fancier (rare & expensive) arm64 servers instead.
It’s great to hear that someone can just grab a rpi4 and run that as a LXD remote with both containers and VMs.
I believe I noted that in my VM forum post but SecureBoot on ARM is very much a novelty still so I would indeed expect having to turn it off for most distros at this time 