As did (does?) TOR. I have the impression that the US intelligence services are always in an internal struggle - some parts wants and needs invisibility, deniability and secure communication - other part wants transparency for intelligence. Both realize that there is no such thing as a safe backdoor.

1. Dubai has extradited to the EU in the past, 2. the EU can easily cripple his business and whatever assets he has in his "home" country of France in a couple of weeks. It doesn't even matter if this is about the alleged real criminal activity on Telegram or political persecution like Musk alleges, the moment Durov decided to stop playing ball his life would be miserable no matter his location.