Wanted to try and do something that didn't want to be done... of course I'm stubborn as cr*p (or "stubborn AF" as you youngsters say) so by the time I'd given up, everything was in a right nasty snarl of a mess...
...okay, it wasn't *quite* as bad as https://xkcd.com/1084/, or Strong Bad's little run-in with a virus:
...okay, so maybe the use of the singular 'virus' there was a little optimistic (ha!) -- but, nevertheless, I decided that between my mess, and a few little annoyances with the OS independent of that (not to mention that Steampunkish Too was running Linux Mint 19.1, based on Ubuntu 18.04), I was about due for an upgrade.
That's how I found out that (a) Intel NUC boards do the same 32bit UEFI / 64bit everything else stupidity that the cheap Chinese Atom SoC systems do... and (b) whatever was in Ubuntu 18.04's installer that was designed to handle that, was removed in 20.04's installer :(
After trying what only felt like a hundred or so different Ubuntu-based distros that you've never heard of (seriously, it was six or less), including a spectacular fail with Peppermint OS Ten where it installed fine, and I then spent the afternoon, evening, and a good part of the night trying to configure it the way I wanted (instead of letting it configure itself the way *it* wanted), I went to shut it down and it immediately froze on the button-click...
...well, that was a waste! /sigh
...I settled on Feren OS. It is installed, it is pretty, and it's running quite nicely RN. Here, have a screenshot ;)