End-to-end encryption managed by the same platform the encrypted messages are routed through can not ever be trusted as end-to-end encryption. The keys, exchanges of keys and trusts must be managed out of band and agnostic to all platforms. There will always be a way for a platform to perform targeted bypass of E2EE if they manage any aspect of E2EE. If platform agnostic encrypted messages are not permitted on a platform that is the first clue to distance ones self far from said platform. Beware of anyone trying to get people to trust E2EE managed by the same platform it is utilized on. Do not even reply to them.