Just FYI, Barrier has been abandoned / unsupported for awhile. Although the last release mostly works, don't expect future support.
Its successor is https://github.com/input-leap/input-leap, and although there have been some coy maintainance on it, they have yet to provide an installable release, due to "reasons".
I use Synergy myself, which is the ancestor of both of the above. Although it started as open source, it has been turned into a commercial product a long time ago, which is why I'm not providing the link here. It's still maintained, for better or for worse, but in the latest release-to-be they revamped the UI and for some reason I couldn't get it to work at all on my setup - it seems to rely on some auto configuration / autodetection gimmickry which simply is not working here. To make matters worse, the new UI is essentially an electron app, which means it has become a lot more bloated. And then there's also the telemetry thing. I've been using the old 1.1 legacy version, holding out hope that input-leap eventually lifts off.