One of the big problems with Hyper-V and Ubuntu in particular is the clipboard or lack of it. I had 18.04 LTS installed with an X Org RDP login. This worked perfectly and I could have a full screen in my Monitor and could copy/paste. Don’t underestimate copy/paste.
It’s a real PITA if you have to use say WinSCP to copy files over. I think WinSCP is excellent BTW but the amount of labour saving that copy/paste has done since some genius thought it up is immeasurable. That and allowing the full screen of the monitor are two highly important things.
Sadly the 20.04 LTS didn’t seem to allow it. Copy/paste didn’t work between my Windows PC (host) and Ubuntu (guest). There’s nothing worse than losing a feature you’ve grown fond of.
If you follow these instructions for creating a Hyper-V 18.04, you get the screen size popup but not with 20.04 LTS. For that you have to follow these instructions!
It’s things like this that suggest why Linux Desktop has never been that successful. You can waste many hours getting simple things working and sometimes like Copy/Paste they break between versions. And this is with Ubuntu, probably the biggest and best known and supported Distro.