@ChelAs battery care practice, decis use to not plug in their phone at night. This was okay for a year... Then we moved to another apartment.
Somehow, due to some kind of ambient environmental condition, phone battery drained FAST overnight at the new apartment. Went from losing about 6% charge overnight to losing about 46% charge overnight. (And it is something about the apartment or its location; battery drain is much less when spending the night in another city.)
Several months of this intense overnight battery drain killed the battery. Wouldn't hold a charge anymore. We had to get it replaced.
And that's why we sleep with a charger next to the bed.