These 3 pro tips made a huge difference for me with the FPS:
1. Remove the factory-installed screen protector.
2. Keep your fingertips well-hydrated. Dry and cracking fingerprints change on a daily basis and are the biggest cause of failed authentications. IMO, moisturize for a week then redo your fingerprints and experience a huge difference! (And then keep them well-moistened.)
3. Instead of scanning each finger as a separate, well, finger, scan multiple finger tips as part of "fingerprint 1", "fingerprint 2", etc.