Unfortunately, "the border", as defined in US customs law, extends 100 miles inland from the coast. That covers the entire urbanized eastern and western seaboards, or 2/3 of the US population.

https://www.aclu.org/know-your-rights/border-zone

My company will give you a blank laptop if you have confidential information on it when traveling to the US. The policy is always to comply and hand over everything if asked so they want to minimize any risks of information falling into the wrong hands.

That policy also applies for traveling to China. So it’s pretty telling that my company thinks the US and Chinese governments are both risks to its intellectual property.

You can setup Syncthing to be able to quickly redownload everything after you reset your phone.