No. Please refer to the third word in the body of my post, which spells "app".
This is another "I WANT EVERYTHING FOR CHEAP!" post
Where? I am not seeing what you're seeing. Feel free to quote my post to show where this is, and please demonstrate how it is "i want everything for cheap!" in all caps.
The "app", as you call it, only subscribes to the services provided. Whether you know it (apparently not), any features you described are on the server side (as to your post title). You are asking about the server, though you seem to not know it. Why else would you post in "self-HOSTED". Applications aren't hosted.
OP already clearly stated he want to use XMPP. What OP is asking is some client features the functionality of Telegram client. Or a fork of Telegram client, gutted out every signle line of code interact with the backend, replace them with a XMPP client library.
I think OP is quite clear that he wants something resembles to Telegram's UI, but works with XMPP instead. The title is just part of the context. You still have to read the body, which uses terms "interface" and "UI". This means he never intend something server side.
I won't say your comment is inaccurate, but taken out of context and misinterpret what the OP means.
Your comment implies that OP wants a fork of telegram server. Which he clearly doesn't since he wants to use XMPP for the server and a fork of the client.