Telegram is trash. Don't use it. It's not provably secure.
Telegram is not encrypted by default and does not support encrypted group chats. What more do you need to uninstall the app? Even Meta-owned WhatsApp is probably more secure.
Out of all IT security experts I've talked about this with, not a single one has recommended Telegram. They mostly recommend Signal, and variably Session, Matrix, Threema, or Wickr.