Ok, through trial and error and a BUNCH on help here and a number of DMs from @kanga_who, I’m finally up and running on the ThinkCentre M72e with Ubuntu Desktop 20.04 LTS 64-bit.
Here are the BIOS settings I had to get in just the right combination in order to get this working:
CMS - No entry in BIOS
Boot Mode: Legacy
Boot Priority: Legacy
Boot Order: HDD first, everything else disabled.
Quick Boot: Disabled
Drive Mode: IDE
Drive Native Mode: Disabled
Compared to my old RPi 3B+, this [email protected]/16GB/500GB tiny system SCREAMS! This was a refurbished unit I picked up from Newegg.com for about $120USD. Thinking back it’s actually less than I’ve put into my RPi 3B+ running a 64GB MicroSD card (and other crashed cards), case, case fan, and upgraded power supply. All headaches aside, it was totally worth it to get this thing going.
All I need to do now is get my Z-wave devices paired with my new Z stick and rebuild my all of my old yaml automations in NodeRed and I’ll be all set to pull the plug on the old RPi 3B+! I can’t wait!