I believe the reason the 5th is usually referenced is that this usually comes up in situations where the 4th is already not relevant. Either because there already is a warrant, or because you're crossing a border (which IMO seems like an incredibly sketchy excuse and would likely not have been accepted by those who originally penned the 4th amendment, but is at least well-established law at this point).

With the court order, you must give the passcode and/or unlock the phone

The thing is, case law has determined that this is not the case. Passcodes are fairly well protected, from what I've heard. You cannot be made to divulge them anywhere in the US, because of the 5th amendment, even with a warrant. Case law is more split on whether biometrics should be offered the same protection.

Though again, this is all my understanding of it having heard it third hand from Americans. Mostly from Americans who themselves are not legal experts, though I think I've at least a couple of times heard it directly from lawyers.