@icedquinn I highly recommend Zulip. Unlike other communication tools (Slack, Teams, Discord) it is based on a long-standing standard which it implements and enhances (email), and is also an excellent member of the Open Source community. I tried out their Docker version and was pretty pleased, then switched to their free hosted version so I didn't have to fiddle with Apache/Nginx/Docker stuff.
@icedquinn Big agreement on this, though. Being the internal utility of a major organization + being open sourced can only help.