The pixels from 6 to 8 use an optical fingerprint scanner, and optical scanners almost universally suck, because they use a tiny camera to see your finger through the display on your phone. Most phones including the pixel 9’s include an ultrasonic fingerprint scanner, which is more reliable, faster, doesn’t flashbang you in the dark, and has the potential to be much bigger (think lower half of the phone is the fingerprint scanner).

I haven’t had trouble with under display fingerprint scanners since I had my S23 (ultrasonjc), but my previous has an optical one and it was the worst thing I’d used.