Maby when it comes out of alpha testing Whitenoise could be something. Or why not Simplex?
Discussion
They're more like instant messengers designed for one on ones or group chats rather than super large communities with tens of thousands of members in. Wouldn't fit the context. White Noise is also way too new.
Everything has to be bridged together with all the other platforms (IRC, Telegram, Matrix, Discord) and have suitable moderation features to protect against spam.
Ok. Than you do maby not like all of matrix but it is a good option for what the project needs I assume. I just contacted you on Matris from @surveillance_switzerland:matrix.org