Immediately setup my iPadOS 15 iPad beside my macOS 12 M1 machine....and it didn't work. At the time there were a couple of brief articles saying just move the mouse off the edge of your screen.
They haven't released this technology yet, so we can't test it out. Just an FYI to anyone who looks to try it out.
As an aside, I have a Mac Mini beside a MBP in my normal setup. My BT keyboard and mouse are connected to the mini. I wish I could do this as easily to jump between machines.
You can! Synergy does exactly this! However, you almost certainly want the fork, Barrier, now, as Synergy has stagnated.