Depends on what you mean by "Daily driver". VMs are reasonably efficient at compute, disk, network. They are annoying when it comes to graphics. I do run Win10 in a vm to do taxes - but I'm glad it is only once a year.

Why not just run Start9 in a VM in your existing Ubuntu server?

I just bought another server with ECC ram for $70 (plus shipping and RAM upgrade). So that is another avenue to consider.