Your Slow and Unreliable Pixel 6 Fingerprint is an Intentional Choice Says Google
https://wccftech.com/your-slow-and-unreliable-pixel-6-fingerprint-is-an-intentional-choice-says-google/
It has been a couple of weeks since the Pixel 6 series came out, but one of the most common issues people have had with the phones is that the in-display fingerprint sensor on the phone is slow and unreliable. At first, I thought this was because Google uses an optical fingerprint scanner instead of an ultra-sonic one, but things are more complicated than that.
Google has responded to a host of user complaints regarding the fingerprint print issue. Funnily enough, Made by Google posted a tweet in which they said that the fingerprint scanner is slower and less reliable for security reasons.