Actually, I think Barrier does, at least between my Mac and my PC. But it's the weekend now, so I'm not going to fire up my work machine for anything...

It does not work well for multi touch, even from Mac to Mac in my experience.

You're right. My use case is also Mac to Mac and Barrier/Synergy does not provide the UC experience. No multi gestures support - and the thing that annoys me the most - trackpad scrolling events aren't mapped one to one, you end up scrolling lines on the target, not the precision you're expecting.

To be honest I'm not sure if Barrier developers could actually mimic that without resorting to some sort of undocumented APIs and/or obscure techniques.

The APIs are all there on Quartz events, it’s just that nobody seems to use them :(

In my case, my always-on workstation is a windows machine, and I also need a 3-button mouse for a decent CAD experience. So, I just give up on gestures and multitouch anyway (I prefer this consistency over having slightly different behavior across machines). Probably for similar reasons, it would be difficult to make barrier work as we wished on MacOS and still be multi-platform.