There are many possible reasons why Face ID suddenly stops working. While it's possible that resetting your Apple ID password had something to do with the Face ID issue, you should also consider other causes. Here are a few things you can try to fix the problem
1. Reboot your device
The first thing you can do is reboot your iPhone. This simple action can resolve many issues.
2. Reset Face ID
We know you've already tried resetting it several times, but it's worth a try.
Open the Settings app, and go to Face ID & Passcode.
Reset Face ID and try setting it up again.
3. Check the camera status
Your TrueDepth camera must be working properly for Face ID to work.
Make sure the camera is clean, and wipe off any dust or fingerprints.
Hold iPhone at a certain angle so that Face ID can recognize your face.
4. Update your software
Make sure your iOS software is the latest version.
Go to Settings > General > Software Update and update to the latest version.
5. Check face recognition conditions
Face ID requires certain conditions to recognize your face.
Make sure the ambient light is not too dim or bright.
Make sure you're not wearing a hat or mask that covers part of your face.
6. Hardware issues
If you've tried all of the above and Face ID still isn't working, it might be a hardware issue. In this case, you need to contact Apple Support to have your device inspected and repaired.
Issues related to resetting your Apple ID password
While it's unlikely that there's a direct connection between resetting your Apple ID password and Face ID issues, it might help to try setting up Face ID again after resetting your password. It's also possible that the security settings were reconfigured after the password change, causing a temporary issue.