Recently I found project twist.com. It is closed source, but i think it is interesting concept for reference.
Combination slack (or discord) template (or maybe mail client like gmail) with old fasion forum threads.
It is look like slack(or discord) but on second level - have threads like misago (not chat)
Here is manifest for async communication: twist.com/async.
May be it will be interesting for misago v4.
ps I'm looking up some software for non-commercial comminity (hiking and cycle club), I love idea of twist but we can't afford paid version for our community.