I just bought a new Mac mini (and Dell monitor) to replace my 2015 iMac. I have them side by side while I set the new one up. I’m not doing a transfer because I want a clean, fresh install that cleans out a lot of detritus going back 15 years and 4-5 computers ago. Anyway, I have a full set of 2 mice, 2 keyboards, 2 monitors and 2 machines side by side, and did nothing to connect the 2 computers except they’re both Macs and I’m signed in with the same iCloud account. And automatically, both mice and both keyboards work on both computers, like it’s a 2 monitor setup. They even know which one is on the left or right. Both cool and disconcerting.
I don't need advice, I just found that interesting.
And shut up with your "what is this doing in the stadium thread" nonsense.