It's been somewhat established that having a wiped or basic phone is in itself sus and reason for them to investigate you further.
What are they going to do if you’re not carrying anything illegal and you’re a citizen? You cannot be refused entry to the US as a citizen and they can’t charge you or hold you without evidence. You don’t have to tell them why your phone is wiped, just stay silent until you’re released.
Have not heard this, whats your source? I don't see how they could determine that because "its a new phone" is hard to dispute.
best case scenario is that a higher court overturns this but not holding my breath.
They can investigate all they want, they can even detain you briefly, but if you are a citizen and there’s no evidence of a crime then they have to let you in.