Modern dell desktops (like 8th gen+) idle around 10W. Raspberry pi isn’t saving much

I’m impressed with that.

I had a Nuc 9 extreme with a 10gb SFP card in it.

It averaged 69w. The Mac Mini I replaced it with uses just under 5w.

A Mini is possible the worst bang for buck. Also, the horror that that is Desktop Docker can’t be over emphasised. I know there are better ways of using Docker on a Mac, but having got something working I can’t face rebuilding it.