I absolutely love Calyx, and wouldn't move from it. However, the battery life even compared to my old iPhone 6S is pretty bad. I'm not even a heavy phone user, I don't use social media or have many apps sending me notifications (only Signal) and I feel like my phone can't even last two days of light usage. My iPhone I could use similary and I could usually get 3 days of usage.
(To be fair, I ran LineageOS without Google Play Services installed, which makes a huge difference, so it's not exactly apples to apples.)