The CEO is Russian. He formerly owned VK and sold it off to the Russian govt iirc. Though, he didn't sell it off without destroying documents containing user info which the Russian govt wanted which in resulted in a warrant for his arrest. Telegram now operates in Dubai with teams working in several other countries like Ukraine. He chose Dubai mainly because of their laws that so far have been favorable to tech companies and not being so heavy handed on censorship.

There are 8 data centers none of which last I read operates in Russia. I think there used to be one until Russia banned Telegram as the company refused to allow access to their servers. The ban was lifted several years later but Telegram still hasn't opened a data center there. And the way these data centers work is chats are excepted and the encryption keys to those chats are never stored in the same location. For years governments like Germany and India have been finding Telegram for either not taking down content they don't like or not doing enough to suppress speech. I believe Germany is in the lead as every year they keep leveling millions of dollars worth of fines.

Of course, feel free to do your own research as a lot of this is off the top of my head what I read over the years and why I remain using Telegram as my primary "do everything" for light social media and messaging friends and family.

I do like the simplicity of Signal though but I always worry about losing my backup data like I did once and would hate to lose all that history and photos shared with text context somehow if my phone ever got lost (knock on wood never happened).

I look forward to Signal ditching the need to share phone numbers and instead use usernames. But for now, Telegram has a lot of flexibility and utility that Signal doesn't have or can ever match due to the focus of said app.