I have a Pixel 7. I think about four or five days ago I started noticing my phone was dying near the end of the day after very low usage. Today I checked Battery Usage, and none of the apps are very high, but under System, Mobile Network is over 70%.
I see many discussions about this on Reddit over the years on different Pixels with stock Android, but no clear solution. I know there was a software update for GrapheneOS today, but I don't remember any other updates about five days ago.