It was a many months transition, and it's finally done
Fun thing, you can actually make a backup of all* your messages, groups, contacts, etc. So before leaving you can have all of your data in case you need that one contact or something
The final red flag was as that allegedly Russian authorities were messing with people's deleted messages. Not for the first time there are news that they could read, modify, delete, see location, and etc. Screw it, this is unsafe, I'm out.
Also, these days telegram is really at the state of a pile of garbage, bloated, buggy, and shady messenger.
My brother, XMPP existed before Web 2.0 where after the cost-cutting way to ship an app was a browser option (browser options help accessibility tho)—where Electron was the most egregious RAM stealer. OMEMO has been around for multi-client double ratchet e2ee since 2015. An ejabberd server can be tuned to handle 2 million simultaneous connects—Synapse folds over like lawnchair at a single user joining a room with a medium-length history.