You should pitch this direct to someone running a project you use. I’m interested as well.

I am extremely uninformed but here’s what I found for slack

https://help.beeper.com/en_US/chat-networks/slack

https://github.com/beeper/slackgo

It appears based on the 2nd link that slack may have an API.

I actually haven’t used beeper in ages. I don’t use many of the chat apps with official bridges other than signal and discord, and Instagram (when I had it) hated that I was bridged and threatened to ban me. Since I’m on iPhone open bubbles bridge isn’t worth setting up for me so I’m not gonna bridge iMessage either. Best of luck with chat and beeper though !! :)

Like any matrix client, it uses their e2ee before hitting the matrix home server.

https://www.beeper.com/

Matrix client that lets you bridge a variety of chat apps. I imagine you’re using slack and at least one of the other messaging apps they support