Mac Carlos Said:
"Safari takes over 6 seconds to load after iOS 15.1. Reset cache, tuned on and off private relay, reset network settings, hard restart of iPhone, even reset address bar to the original top."
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Clear Space:
Try clearing internal storage though use of the following:
What Space to Clear:
A. Clear Temporary Internet Files:
Clear your Temporary Internet Files(Cookies & Cache) of Safari:
Also...
B. Clean TV and Music Libraries:
Remove all unneeded files from your TV and Music Libraries. Full-Movies take up 2-4GB typically, and a bunch of those would take up a load of storage, ideally. So, if you have any movies that are not needed, then delete them.
Also..
C. Clear "Other":
Clear the storage named "Other". It basically contains unnecessary files such as caches that are used for system ease of use - all of which gather over time: How to Clear "Other" in your iPhone's Storage - Use Backup - User Tips. Caches would be being used for remembrance of application use. So, clearing other may be the way to go about this, as it would be performs through use of a computer.