People use Discord and Slack for different reasons.
If you want to create an alternative — the place to start is NOT E2EE (end to end encryption).
A place to start is understanding all these different types of users and use-cases. And then deciding which of these user types you are making the software for.
Some of them need E2EE, but some do not.
@reiver@reiver ⊼ (Charles) 
> People use Discord and Slack for different reasons
My impression is that for most communities it's an alternative for web forums, not for IM or IRC. So for these folks, Lemmy, Discourse or nodeBB might be a more helpful suggestion than XMPP or Matrix.
I noticed this back when Slack pulled their bait-and-switch by turning off their IRC and XMPP bridges, and wrote up a page of replacement options;
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