[xashor]

With Signal, if a the numbers registers a new account like in this attack scenario, 1. the attacker cannot access old/pending messages (as they are always encrypted), and 2. the person on the other side of the conversation gets a warning that the keys have changed, thus need new verification before continuing the conversation. So, Signal is more secure on that front.

[mesaframe]

Telegram got two factor support which a user can enable anytime for security.

[Maakuth]

Also, there's a PIN code you can use to protect from transferring your number to another device. This is periodically asked by the client app so that you'll remember it.