Possible solution: An app that dumps / restores the phone to a remote site, all e2ee.
Wipe your phone and factory reset before you cross the border, then restore afterward.
I did something like this, though not as an app. It was pretty cumbersome to do. Next time I'll just bring a travel phone.
I think with iOS you can do this pretty straightforwardly
I did something like this, though not as an app. It was pretty cumbersome to do. Next time I'll just bring a travel phone.