It's highly unlikely that the Canada Border Services Agency, of all organizations, is able to defeat competent modern crypto implementations.

It's also quite unlikely that they can circumvent a basic `tar -c /dev/block/* | gpg -se ...` scheme that's trivially doable on unlockable Android phones. (Replacing the bootloader with a maliciously crafted variant that returns false partition data after bootup would work, but once again: CBSA.)

You're probably safe if you just do an iCloud backup and wipe followed later by a restore.

Certainly do replace the SIM card as soon as possible though, IMO. Unless you can verify it somehow.