My last phone with standard Google Android had a 5000 mAh battery while the new degoogled has one with a bit more than 6000 mAh I think. Even then I feel the overall increase in battery life cannot be explained with hardware only. Without watching videos or playing games, I only have to charge my new phone every 3-4 days. And I've background apps like syncthing running all the time. I've just checked there's actually a few other open source forks of android other than LineageOS. If you're disappointed with it.