IIRC anything with the fingerprint reader gets complicated because of the signing keys Apple uses to help protect the device against unlocking attacks.
There is nothing complicated about simply not having a fingerprint option. If the main machine knows it cannot trust the fingerprint secure enclave, then there is nothing complicated at all about simply, not trusting it. The user simply has to unlock the phone with a pin or pattern etc. This does not, in anybway, require bricking the device. That is simply a deliberate and hostile act of aggression against the user.