DeMArcus I have a Pixel 7 Pro that I loaded the experimental version of GrapheneOS on yesterday. Although 1 day is way to small a sample to do any type of statistical analysis on, yesterday I finished the day with 72% battery life. With my Pixel Pro 6 and GrapheneOS, I would end the day with anywhere between 65 and 75% battery life. So while 1 day does not indicate a pattern, based on my observation yesterday, I would say battery life is similar.
This is with adaptive brightness, wifi, lte and bluetooth all on. Although I didn't use a stopwatch to keep track, if I had to estimate, I would say that I spent approximately 3 1/2 hours on the phone using bluetooth (air pods pro), 1.5 hours poking around to see how the hardware worked compared to the Pixel 6 Pro, and 1 hour or some browsing the internet. It took me approximately 3.5 hours to backup my Pixel 6 Pro, flash the Pixel Pro 7 with GrapheneOS, and restore the backup to the Pixel Pro 7. SeedVault is notoriously slow. The backup, restore, flashing time should not be included in the battery life time, since I had the Pixel 7 Pro on a charging stand during this process.
Disclaimer: this was my experience, and your mileage may vary.