@0xabad1dea (mute acknowledged; replying anyway) AFAICT, there are many jabber clients and servers that fulfill that checklist and have for ages. It's also got a bunch of the nice-to-haves, and options for most of the other features.

IMO, Pidgin did a terrific job as a client, and there is support for voice. Screen sharing is available but it seems there were some security issues with some of those plugins. FWIW, I'm not a fan of the large window interfaces used by Teams, Slack, etc...

@ratsnakegames @0xabad1dea @gabboman I'm not sure it's true that adding video/screensharing would significantly increase cost. I think the centralized service could facilitate establishing the network link between the parties and have them send the feed more-or-less directly. But I may simply be mincing words here - that could be interpreted as making it distributed.