I am curious.. have you tried Zulip? It's basically Slack but with threads instead of unsearchable topic-changing conversations under the same hashtag.
Zulip is ugly as hell but it *feels* better than slack.
Discussion
Haven’t. Will look into it
Also rocketchat which I deployed instead of zulip when I evaluated them both, but if I had it to do over again now without the friction of user lock-in, I'd probably go with Matrix.
