Phone is freezing since got it updated to ios15
Phone freezing due to new update any help
iPhone 7 Plus, iOS 15
Question marked as
Make absolutely sure you are not running any App Store VPN or security apps. They most probably will not be compatible with iOS15
Force restart https://support.apple.com/guide/iphone/force-restart-iphone-iph8903c3ee6/ios
If no better
Backup and restore (using the computer method preferably)
(1)How to back up your iPhone, iPad, and iPod touch – Apple Support
Unlock your SIM PIN if it has one
(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 problem remains then arrange a repair