And this is why part of my plans for any international travel are to simply have a physical notebook with phone numbers to trusted friends/family and to buy throwaway devices on the other side (phone and chromebook or similar).

TBF, similar mindset if I ever attend defcon, etc. as well.

The simpler option is to fly through a place with USA pre-clearance. At least in Canada you can revoke you application to enter the USA at any time when in pre-clearance, and there are very limited instances when you can be legally detained by CBP (mostly around being an immediate threat or the CBP officer has evidence that you broke a law such as attempted smuggling).

I currently fly to the USA through Canada and if CBP ever insists on seeing my phone I will revoke my application to enter and accept that Im most likely banned from entry for a while.

The crazy part is that you might be denied entering the country you don't travel with a device...