Welcome!
BFU/encryption won’t offer protection if the owner can be coerced to unlock the phone or decrypt data. Some jurisdictions have mandatory decryption or data access where the owner of a device can be punished if they do not unlock their device. If police, military, security forces, border agents, gangs etc applying coercion is a concern, sensitive data should not be carried except in a way which it cannot be found.
There are a few threads in this forum about how to cross borders (airports and so on), and these contain some solutions/suggestions that may fit your situation.