hello Avaris,
the FaceTime front camera is not directly involved in starting the Face.ID service. It's just a helper function to see anything in the scan circle. The fact is, however, that the front camera is enclosed in a metal braket and constitutes the entire FaceTime assembly.
You can unfasten the bracket and replace the front camera without losing the Face.ID function. Unfortunately, if you damage any of the elements, the damage may be irreversible. Take this into account when trying to do it yourself or ordering it in a repair shop. I believe you will quickly discover that most unauthorized repair shops are not competent enough to perform such repairs (they are just learning on their clients).
Call, search, do not be afraid of shipping repair services, sometimes you can meet there talented technicians and enthusiasts of the highest flight.