Closest answer I found on the internet was this:
https://www.reddit.com/r/galaxys10/comments/c1uf52/can_the_sim_card_affect_battery_life/
Can the SIM card affect battery life?
i was wondering if the sim card can affect the battery life, as it sucks on 3g/4g and at home on wifi seems ok, i've sent the phone to the samsung service, and since i changed my sim card...my old phone (iphone X) seems to have better battery life...is it possible?
sivartk
5 yr. ago
If you are in an area with a weak mobile signal, the phone can be constantly searching for a signal which will cause battery drain pretty quickly (I.e. in the basement of a hotel, etc.). If you have a strong signal, you shouldn't notice a difference between being on LTE or WiFi as far as battery consumption goes.
deleted
5 yr. ago
No in the least.
So, things not working says that you might be configured for the wrong network, and the phone is eating battery trying to find whatever network it is searching for.
This is very rudimentary, as many internet searches are, but it suggests that you get help in proper activation, whatever that means. Someone would have to have a good understanding of your phone and the carrier.
Good luck.
My ex's battery on an old phone was tanking at work. She put it in a locker and it was wasting battery searching for any signal (that's the hint, searching for a signal/network) and the solution (not yours) was to put it in airplane mode when locked up behind metal. (the old tinfoil situation)