Really hope Google release the face unlock function in the December security software patch update. If so, it will be really interesting to see if the face unlock system can match or come close to the Pixel 4 XL version which was absolutely incredible - insanely fast and accurate - much better than Apple's face unlock system imo. Powered by the Soli radar chip as part of Google's Soli Project if I recall.
In the end, I think security privacy weakness became the primary issue, allowing for face unlock with eyes closed - and main reason it never made it to the Pixel 5.
Personally, like others, I am definitely missing face unlock on the 6 Pro compared to Apple.
The FPS has never failed on me - I would say don't rule out a 6 or 6 Pro based on that buying decision alone but it is noticeably slower with Google opting for the under-display optical version instead of ultrasonic version.
The only other Google software update that would really grab my interest is improving the quality of video on the 6 Pro, it is great and much better than previous Pixel's but still not as impressive as Apple's video quality.
Thinking about nice-to-have's on a future Pixel is a flat screen, 3.5mm headphone jack and stylus (no chance on both!) just because I'm old school! The 6 Pro definitely lends itself to stylus use, I'm going to buy a new one.