found out about #Fluxer, another #OpenSource #Discord clone. caveat: i have not used it yet. but i know people may not be satisfied with #Matrix and/or #Stoat so this is another idea to explore
some info:
https://blog.fluxer.app/how-i-built-fluxer-a-discord-like-chat-app/
https://github.com/fluxerapp/fluxer
you can get the app at fluxer.app
Haven't started using it yet, but what I know so far based on the blogpost:
* it's #FOSS
* the lead developer wants to implement #federation at some point (though Stoat's devs may also be considering that; I dunno)
* the lead developer wants to implement public forum channels (addressing one big problem of organizations/devteams only using Discord as their public-facing thing)