GrapheneOS doesn't come doesn't come with anything keeping open a push connection and barely has any scheduled work. Waking every 8 hours for update checks doesn't use significant power. It doesn't have better battery life due to any major efficiency improvements but rather the lack of bloatware.

Installing sandboxed Google Play on GrapheneOS results in having a push connection for Firebase Cloud Messaging and doing a lot more work in the background. Idle power usage will still tend to be better than the stock Pixel OS, but adding more apps to match their bloatware will make it comparable.

Battery life heavily varies based on apps, networks and OS configuration. Many people end up with far better battery life on GrapheneOS and many people end up with far worse battery life due to differences in how they set up their devices. It's easy to end up with either result with simple choices.

Installing Signal in a profile without sandboxed Google Play and granting the power optimization exception it requests is enough to destroy battery life and end up worse than the stock Pixel OS. The power efficient choices are either using Molly with UnifiedPush (Signal fork) or Signal with FCM.

@GrapheneOS this was pretty much my experience in the beginning when I started using grapheneOS as my daily driver with the main Signal app. After switching to Molly and using UnifiedPush, I stopped noticing battery drain 👌🏽

@realestninja @GrapheneOS
What is the easiest way to switch while retaining my chats?