I think I'm at low risk.
I power my phone off prior to arriving in the US and keep it off until I leave the airport.
Under US case law, you can be compelled to give up a thumb print or face ID with a search warrant. But you cannot be compelled to give an unlock code, because the code information is testimony, and you have the right to remain silent.
If they insist on seizing my phone unless I unlock it, my plan is to ask for a lawyer, shut the fuck up, let them seize the phone or whatever, then sue them later to return it.
This plan works for me because I'm a US citizen, and I have an absolute right to enter the country. If you are not a citizen or LPR the local CBP officer has the discretion to refuse admission even if you have a visa. So that's a real consequence to non cooperation.
Don't lie to the feds about not having a phone if you really have one. That's a separate crime all by itself.