This was the year I tried out Darcs & Pijul. With conflicts being less problematic & easier to collab without patch order mattering, you gotta wonder why all of this effort is still put into bolting stuff atop Git instead of moving on & helping the tooling in this space.
Second place would be Movim as a decentralized social media platform built atop the XMPP server you are already running.
Which is largely whether or not the eventual consistency model or not is the route to take. Is the resilience for chat worth the explosion of storage & preformance cost of sync/search & maintaining all that data amongst all servers? Or is limited/functional sync without always duplicating the entire history with the occasional out-of-order message & missing old attachments good enough? Is ephemeral chat okay to save resources which in turn makes it more feasible to self-host on lower-end hardware or is it better to trust a couple big servers with massive storage who probably have admins?