Hi. I have a Google Pixel 3a running PostmarketOS https://postmarketos.org/ and it holds up pretty well. My phone lost 20% today with light usage and will maybe lose 60% if I scroll social media a lot.
I was actually surprised it is this good. I reinstalled recently and before the reinstall I had much worse battery life (Maybe 8 hours with normal usage). I think it was because of Syncthing running in the background.
It is also possible to use s2idle suspend which will improve the battery life even more but you will not be able to receive calls during suspend (though that may also be fixed in the future)
I was actually surprised it is this good. I reinstalled recently and before the reinstall I had much worse battery life (Maybe 8 hours with normal usage). I think it was because of Syncthing running in the background.
It is also possible to use s2idle suspend which will improve the battery life even more but you will not be able to receive calls during suspend (though that may also be fixed in the future)