Is there an alternative to Microsoft Teams?

Question

Work organization

Actually, in the current conditions (NVO in Ukraine), there may be problems with working in Tims. Therefore, the question is - is there any sane self-hosted solution? And I'm not so much talking about voice communication (although it, of course, is also needed), but about teamwork - working in different channels of teams / projects, creating a wiki for projects, exchanging files within projects, tasks for performers, etc.

Answer 1

Redmine has always been used ...
Maybe you should just finish it.

Answer 2

Text & Voice - rocketchat, mattermost
Teamwork & Wiki - Youtrack
File Sharing - OwnCloud/NextCloud