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.
I think Signal shot themselves squarely in the dick by removing SMS functionality.
Previously, you could use Signal as the primary SMS/messenger app. Any conversations with other Signal clients secure. Conversations in SMS/MMS? Marked as not-secure.
But, out of some purity concerns, SMS functionality was removed and the dev team focused on adding useless shit like "stickers" and then the pin-code harassment.
Signal adoption plummeted as intended (?)