Weren't the HPLIP drivers for CUPS universal? BTW, an Alpine VM would be far lighter and maybe still have all the drivers.
HPLIP: I believe they are, yes. I could just as well have configured it that way in the VM, I agree. About the Alpine VM: absolutely correct, and as stated in the article I would probably benefit from having a much slimmer VM. This was initially just a test case (and benefitting from the one-click install via UTMs gallery), but because it 'just worked' I decided to for now leave it as is.