Yes, someone thinks they know. Tebany Yune:
Battery drain, unfortunately, is a common problem for iPhone users
Uh, it’s a problem for all smartphone users. Duh.
If your phone is always running low despite your best charging efforts, you might need to take it to an Apple Store for repairs or a replacement.
Might. Low Power Mode and Do Not Disturb are big battery savers. They’re free.