Android natively doesn't have support for face detection in hardware. It hints that Andorid Q will have that feature. but not sure.

You can achieve FaceDetection in android using Vision SDK or firebase facekitML. Thats is different approach. you can look foor.

Android is having face detection since icecream sandwich. It depends on front camera quality and uses 2D renderer to authenticate which someone can fool out with user photograph. You need to concern about security issues.

Further more some vendors like Samsung,Huawei using their own technology in device for facial recognition.Where Samsung is using iris-scanning technology in their devices.