Like others have mostly said, Mint is a great choice.

All the different distros can basically all do the same things for the most part. The main differences between them are mostly philosophical and don’t matter to a new user.

Once you get comfortable with linux, you can easily switch to a different distro if you get annoyed with something.

For now, just choose a popular distro that you think has a nice user interface.

I think mint, popos, and Ubuntu are all great choices.

For the US, my understanding is that citizens can refuse, but if you do they may hold you for some time.

Non-citizens may be denied entry if they refuse to hand over their device.