Battery Drain overnight

That sounds strange. I can read around the web that several are having issues with battery draining on iOS 14.

If you have the time and courage for it, then you can take an iCloud Backup of your phone, and restore your phone to factory settings, it can sometimes be the solution to those "diffuse" problems

Here are some guides:

For Backup - https://support.apple.com/en-us/HT203977

For Restoring - https://support.apple.com/en-us/HT201252

Hi

Have you looked under Settings -> Battery there you can get a very good indication of what is draining your battery at night. Do you remember to restart your iPhone once in a while? It can sometimes help too.

The problem may also lie in the backup. I personally would do a clean factory reset, without back up - I know it can be cumbersome, but it usually solves the problems unless it is hardware related.

Do what a half billion other users do:

Charge the device while you sleep.

Not everyone has the opportunity to do so. Maybe thread starters work at night.

Charge it when not in use.