Downgrade from iOS 13.4.1 to 13.4

Hello guys,

I would like to downgrade my phone software from iOS 13.4.1 to 13.4. The latest update is draining my battery significantly, especially during idle (e.g. overnight). My phone is losing charge @ 3% per hour when completely not in use. This is much higher than the less than 1% per hour that has always been the case with my phone ever since I bought it in 2016.

There is no setting that I have changed, and no new apps were installed post the update. So clearly it is the update that is causing battery problems on my phone. I am unable to find an official link (Apple site) to download iOS 13.4. Unfortunately, i did NOT create any backups before the update. Please help.

iPhone 7 Plus

Battery Health: 85%

Thank you.