I have updated my Pixel 5 to Android 12 Beta, and in the last update, the "app" or service called "dex2oat64" eats too much battery.
I found some thread in Reddit, but they also don't know the answers like me.
What is this app/service?
Android Enthusiasts Stack Exchange is a question and answer site for enthusiasts and power users of the Android operating system. It only takes a minute to sign up.Sign up to join this community
dex2oat is a utility used when installing or updating applications, so that was likely just a remnant of your "Android is upgrading" phase that you saw after the initial/first reboot after the system/software update.
Most likely you have just installed Android 12 and it's setting up everything/caching process in the background. See if it get fixed in a few days (3-4 days usually).