the Matrix stack. BUT! It’s hard to set up and nobody uses it!

Is it really that hard? For me it was just downloading an app and creating an account–easier than setting up Facebook Messenger. I think it doesn’t yet have the network that Messenger/Signal/Whatsapp have, which makes it harder to use with others, but setting up has been easy in my experience.

Unless every browser decides to allow scripting in a less shotgun-your-foot language, javascript will remain widely used.

It’s called web assembly, and all the major browsers (Safari, Chrome, Firefox, Edge) now support it. That’s not to say that Javascript is going to disappear, but other languages might take over much of its marketshare.