I‘ve been looking into this a bit and whilst i haven’t really tried any of the alternatives, i did collect some notes:

possible contenders

• zulip
  • apache-2.0 self hosted more work focussed
• stoatchat (formerly revolt)
  • AGPL-3 self hosted
• teamspeak
  • proprietary … self hosted older ts3 with ts6 announced
• mumble
  • license seems foss - self hosted
• spacebar
  • AGPL-3 self hosted
• return to irc or xmpp

probably no

• matrix - could not decryptinator
  • a hassle regarding voice
• peersuite
  • very very young and not really ready
  • lemmy.dbzer0/./post/45470657

DO NOT

• mattermost
  • play stupid games, win stupid prices
• guilded
  • owned by roblox
• slack
• discord
• ventrilo
  • proprietary - not selfhosted - no linux

please let me know what y’all think