If he's so concerned with privacy, why can't you use Telegram without giving away your phone number?
The FBI tried to bribe a Telegram engineer to create a backdoor into their software to control and spy on what was happening on their platform.
https://video.nostr.build/b1021ae093747e50de02df887973dd7a43fa35435ca546951862ee9aac44832d.mp4
Discussion
What I thought. They're far from being privacy focused, they're just another flavor of Meta and the legacy social media. With more Blackjack and hookers. But even the hookers have to give their phone number, so...