Battery problem

Ah, okay. It might be a different problem.

These are two basic troubleshooting steps you can try:

A Forced restart of your iPhone, using these instructions:--> Force restart iPhone – Apple Support

If, after testing it, the issue persists, something could have gone wrong during the latest update procedure.

I would try to install a fresh copy of iOS. To do this, create a full backup of your iPhone (1), then restore it to factory settings (you need a computer to perform this step) and, in the end, set it up as new (2).

When done, restore data from your previously made backup (3).

Follow the instructions provided in these support articles:

(1) How to back up your iPhone, iPad, and iPod touch – Apple Support

(2) Restore your iPhone, iPad, or iPod to factory settings – Apple Support

(3) Restore your iPhone, iPad, or iPod touch from a backup

If the issue still persists, contact Apple Support directly, using this link:--> Get Support , or make an appointment and have your device inspected at an Apple Store or AASP (Apple Authorized Service Provider) among this list:--> Apple – Location Selector. After checking it out, they'll give you all the available options.

Regards

Giulio

Apple Support Community Forum

This is Apple Support Community forum, for a user to user interaction for information & idea sharing between users, if need be, extend support on technical knowhow in handling Apple products from a more experienced fellow user, This is not the right forum to discuss with Apple Inc.

Your battery might be "tired" and might have unpredictable behavior.

Go to Settings>Battery>Battery Health>Maximum Capacity.

Tap there. What percentage is shown? If it is close to (or under) 80% , make an appointment at an Apple Store or AASP and have your battery replaced.

Regards

Giulio