Overheating

Update your iPhone to iOS 14.0.1 if you have not already.

Try and Force Restart your iPhone exactly as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

Axel F.

Check out your battery usage

1. Open the Settings app on your iPhone.
2. Scroll down and tap Battery.
3. Scroll down to view battery breakdown.

Update your iPhone

Update your Apps

Force your iPhone to restart