iPhone 15 - latest iOS. Weird button between island and phone edge - eviltoast

Greetings.

Since the use of my new 15 pro I am seeing this telegram button between the Dynamic Island and the top edge of the phone in locked situation

When unlocking the - button/text balloon/whatever it is disappears to the top. What could it be ?

Tried to remove it by taking off the notification of the telegram app, checked it ain’t a widget which it isn’t. How to remove it ?