if you press volume up, then volume down, then hold the power button until the power slider comes on, then it will disable biometrics until next unlock
For GrapheneOS (custom android), there is Lockdown button next to power off and restart which does the same thing. I think it may be on other Android phones as well but not sure.
Yes, and it may be a good idea to have it just in case. But the courts in the US so far mostly ruled that police forcing you to give biometrics to unlock is fine, as it is the same as fingerprinting you when you are arrested. But forcing you to give pin/password is the same as testifying against yourself, which is against the 5th amendment. So they usually can't make you to give them a pin/password. At least in theory. Still better to have it in practice.
I just tested it... it's the same combination for a fast shutdown. Up > Down > Hold Power (1 second hold), then you're introduced to the option of sliding to power off. If you exit from that prompt or just leave the screen idle for about 10-15 seconds (I didn't count it) you'll be forced to enter passcode.