@movq@www.uninformativ.de When I quitted WhatsApp I went to Signal and this works really nice. You also have a native Desktop App and no outages so far. You can create bots for automation, which is a bit easier with Telegram, but hey, you can do that (Octoprint I hear to calling for filament change :-))
With Signal you can also donate if you like and help keep it running. For most people the stuff has to be easy. XMPP is not, Matrix is ok, but you need to create an account which is for some users a hassle, “abother account, again?” (they don’t realize that Signal, Whatsapp is also an account, just their phone number is the username, but it is seamless in-transparent process to the user how it is done), Synology-Chat: You can provide credentials for them. The problem is see is, people want to share things. And when it comes to share stuff outside the eco-system, most people have bad experience or don’t know how to do it as sharing to others it often hidden behind a second or even third screen tap.