Changes in software such as upgrades may introduce new features which may add to power drain and heat generation. Check Settings > Battery feature to see if there are apps or services running that use a lot of power. If there are, decide if you need them running all the time, can turn off a service when an app is in the background, or disable the feature completely. Read this support article to learn about the battery health feature. —> iPhone Battery and Performance - Apple Support
Refer to this post for good tips on reducing battery use on your device --> iPhone 14 pro battery health reduced to 9… - Apple Community
Addendum to #11. Use 4G/LTE instead of 5G. Use 5G with your iPad - Apple Support
Here is a related post in the context of device heating. --> iphone pho max 14 phone gets hot - Apple Community