Telegram is not less secure, this is misinformation. Telegram is less secure by default; it has a worse UX for secure messaging, as a deliberate choice to improve default UX for new users.
IMO if your app is less secure than your competition by default, the app is less secure, period.
Telegram is said to have been given authorities access to user data [1], despite the fact that they advertise the opposite. I guess that’s what happens when your app is not encrypted E2E by default.
Also, they have used their own encryption algorithm in the past (I don’t know now) instead of the well known and proven algorithms out there. Something highly criticized by experts, back then [2]
I tried using secure chats but the UI is nearly unusable. E.g. secure chats are established between two specific devices and can't migrate, so it would make sense to let a currently "active" client (the one the user is currently interacting with) respond to an incoming chat request. Problem is, secure chats were being unpredictably picked up by random devices logged in to my account, so most of the time I couldn't even see any messages.
