I also have problems with one machine, it just refuses to see the others. It might have something to do with the firewall or SElinux, but I’m not sure.

No, it works on other setups too! I have used the regular kde connect app with enlightenment DE for example.

KDE Connect: An app for iOS, android, pretty much every flavor of linux, windows, etc. that lets you connect any devices together to share files, show notifications of other devices, use your phone as an input device(keyboard, mouse), control multimedia applications(start, play, stop, etc.), trigger commands, and everything else if you make a plugin for it.

No idea why this news is making the rounds, duckstation switched to a nonfree license long ago and was forked from the last free release as a consequence. No one is using the og anymore to my knowledge.