
I don’t believe you can be compelled to provide a password. That does after all (at the very least) constitute speech. And freedom of speech is also freedom of non-speech, they can’t make you say something.
They will however try to make you do that… In many situations authorities are allowed to lie to you. So that’s sucks. They can tell you that you’re required to unlock your phone, you just have to know that your not actually.
Also they can’t make you say anything, but they can make you do things, like for instance “put your finger here” or “look into this camera”, which is why biometric unlock is unsafe around cops.

I hate to say it, but this is somewhat common for security measures. Anything that has low level control over a system is inherently an additional vector for attack, it increases your “attack surface”.
Now if designed properly it can certainly be helpful and reduce your vulnerability, but bugs in the system could also leave a user more vulnerable than they were without the additional “protections”.