Ubuntu is fine for a VB host. But I'd suggest, you do a search here in the forum for "Proxmox". That should give you a good overview, how reliable this solution is. Btw. I'd say Proxmox as host and HA-OS in the VM is a good sytem, it's kind of the go-to solution here in the forum for virtualization on mini PCs.
And there are a bunch of really useful scripts for install and maintenance around for Proxmox. 
Here is the the topic for all your installation needs with Proxmox:
I highly recommend that solution, running it myself for over a year without any problems! Beside that I chose a dump location for the PC and now have to crawl under a cabinet to clean it... 
