This is why review sites need to stop focusing on how many megapixels a camera phone supposedly has. It's become a meaningless spec foisted on us by marketing departments. Instead, reviewers need to be talking about sensor size and aperture.
When it comes to consumer technology, it's not unusual to see a new device lagging behind its predecessor in some areas. In this case, early camera comparisons have shown that the Pixel 10 is some steps behind the Pixel 9 in a key area.