Stoat (formerly known as Revolt) is a selfhostable, FOSS replacement for discord [Group chats and voice channels you can join any time].
Cool new name, however not as easy to use in other languages.
Voice chat is stil not officialy implemented.
Self-hosting there. Apparently nothing to do for you if you had already hosted before the name change.
The Android app has unfortunately disappeared (not been updated) on F-droid.
Edit: added short description for clarification


Thank you for the info. I looked at people discussing Matrix for ages here and nobody brought this up? What the hell?
Do any of these options offer screen sharing with audio? That’s literally the only thing I care about in terms of one on one chats that only Discord can do.
Well, this is kind of work in progress for XMPP and DeltaChat doesn’t support it. But you can for example try out https://movim.eu/ which is a webbased xmpp client (with PWA app) which does support screensharing in small group calls.
Matrix stans mentally block out the many issues it has, so take everything they say with a grain of salt 😅