I actually paid for synergy because I was using it extensively back in the day (probably about 10 years ago? Maybe less? IDK. Long enough that I don't care to remember when); and after an update I realized the windows service portion had a bad memory leak. I don't reboot my PC very often, so I kept getting memory errors despite having more memory than the average (I believe it was 24G at the time, when 8G was considered "good" instead of it being the bare minimum that it is now).... I couldn't even always fix it by restarting the service, since it was some kind of memory mapped file or something that was causing the problem, so it didn't register normally that the process was consuming the space. The only way to fully resolve the problem was to disable the service (or remove the software) and restart. So I abandoned synergy for a long time because I wasn't sure when they would actually recognize the problem and fix it.

I got a notice late last year that synergy had updated and my license was going to be given a free upgrade so I could use the newer version at no extra cost, so I figured it would be a good time to try it again, and I had a situation come up in December (ish) where I actually wanted to see if I could get it working; I couldn't. Now that I'm running exclusively multi monitor setups, synergy's configuration doesn't actually give you the option of setting where your screens are connected individually or anything, it just shows each PC as a single display, and for the life of me, not only could I not get it right, but I couldn't even find the trigger point that would move my mouse and keyboard controls to the other system. Even if I managed to get them over there, I had no idea how, and I had no idea how to get back.

So I disconnected it entirely and I'm back at square one. I bought a multimonitor KVM to fix another problem and it reduced or eliminated my need to use synergy.... But I still want synergy to work (or something like it). Is barrier more robust?

No

I don't usually get my hopes up, but yes, it is a wonderfull feelling when it happens.