I have incus running on a Pi 3 Model B Rev 1.2 - this device is about ~6 years old. This is installed and running on Debian Bookworm (I deliberately picked Bookworm as it has incus support - earlier versions will require a lot more under-the-hood work to get it going). I don’t use Ubuntu, but I am sure Incus would work with that too.
I have been running incus (from zabbly repo) on RADXA’s rockpi4c ARM embedded board that that is 2+ years old. I installed dietpi on it (debian/bookworm based). A great distro for embedded boards. There were times I had to reboot. I wrote this article on ovn network setup completely built on this embedded board ( https://tinyurl.com/rockpi4c ) IMHO, embedded boards are great to play around and geek out This board doesn’t run vms though, only containers.