Comment by marcosdumay

You can not use a DH key exchange, and create the symmetric key by some procedure that is predictable, or encode the symmetric key with the government's public key and send it to them.

It doesn't stop being end-to-end when you add another end. We often do group chats that way.

Or you can create a side-channel and send al the data there. That would stop it from being end-to-end.