I use one of these to control 2 PCs and one laptop with a single keyboard and mouse. It could actually run a 4th machine off the same keyboard and mouse if I wanted to cram another into my workspace.

Sharing two 4k monitors between the three as well, though the screens have nothing to do with the switch controlling keyboard and mouse.

Used some double sided tape to attach the little controller switch to the top of the docking station connecting my laptop to the displays and network as it’s a light little thing that would fly all over the place otherwise. Been using the same one for over 2 years now and it’s been working great!

Tried some more expensive solutions in an attempt to tie my monitors and network together along with the kbm and everything I tried had some kind of unacceptable compromise, like bad video quality.

+1 for reolink. Works great with blueiris and has its own app as well. I’d recommend the basic 1440p model, which should run around $50 US on Amazon. You’ll need ether net cables and a POE switch to run them, also not very expensive. Stay away from the zoom versions - in my experience they kind of suck. Been running 8 of these for about 8 years now and they’ve been very reliable. Running both the native reolink app and blueiris on Android, Ipads, and PC, and they kick the dog out of that Ring junk - works great and easy/cheap to add cams and really place stuff when needed.