The only technical solution, not that I have any first hand knowledge of this, would be a remote desktop server running in the secure enclave. Basically everything you do on your phone can be viewed remotely by law enforcement and it seems they only need a warrant if they want to try to use it against you in court. 60 frame per second updates on most iPhone screens, means when connected, it takes 1 frame out of 60, combines each of the 59 frames and sends those over to the secure enclave kernel. Basically just like remote desktop operates. There are other debugging features that can be enabled for the virtual keyboards and so on that can leak information.

Sure, you have end to end encryption but that's hardly all of the threat vector.

People need to accept that it's far more than metadata, we have no privacy, and in a way we are all locked inside of these virtual jails that keep people locked in like drug addicts.