Sorry for the late reply.
I mentioned the battery life because in the past I have had a similar experience as you.
Now I can use my FP4 throughout the day with losing 40-50% of battery if I don’t use my phone very intensively.
The battery drain problems started in my case after upgrading from LOS 22.0 (from the top of my mind) to 22.2, with GAPPS. Back then, I have tried many things to resolve it, including airplane modes, battery saving mode, switching cellular data mode (4G, 5G etc.), factory reset, clean reinstall. Finally, it was resolved after I installed CalyxOS. Some others mentioned that had worked for them, when they had similar problems, also with the official FPOS.
Then there were the problems with the CalyxOS developers, where you may have read about. I stayed at unmaintained CalysOS for a while until LOS 23 was released. Then I installed LOS 23 with GAPPS and it was a big releave that the battery problems did not come back. Recently, I upgraded to LOS 23.2 and still everything is fine.