I think I may have created the perfect flip-flopper setup. I have now mounted my M1 Mini to the back of a 27" 2560x1440 HP monitor. The Mini gets the HDMI input, and the PC on a table next to my desk currently gets the DVI input (although that will switch to display port when I get around to it).
Now if I decide I want to switch to using the Mini, I only have to select the correct input (fairly straightforward on this monitor, thankfully) and push my PC keyboard back so I have room for my wireless Logitech K380.
I do miss having the lovely silver brick to look at, and the plastic mounting bracket probably scratched it up a little. It may stifle airflow a bit too, but considering the Mini's cooling is probably overkill for the M1, I'm not terribly concerned. Oddly, the sound from the internal speaker seems to be amplified and is actually pretty passable. In essence then, I have an iMac
But, of course, without the sleek aluminum case and little black Apple that makes us all want Macs in the first place.