Nextcloud looks really great and it has a chat / video chat too, I want to give it a spin in the future, as it also allows you to self-host a lot of things that people usually outsource to Microsoft, Google or Apple.
The video calls in nextcloud are a bit....hard to make work flawless, lol. You also need some amount of ram and cpu in the server.
I think you always need some amount of ram and cpu in a server... ;D
Well, it's a shame if those video calls aren't working nicely without some fiddling. I'll still set up a Nextcloud at some point, for all that other stuff like calendar, contacts, office, chat and file sync. Kinda enjoying the benefits of cloud synced data, but without a corporation hosting my information and selling me to the advertisement hyenas.