I had been running betas of 15 and the the official release and found access to this site (and others) terribly slow on both Wi-Fi and Cell. The problem is being caused by the Private Relay feature.
What it is:
How to turn it off:
What it is:
Apple introduces iCloud+ service with Private Relay, Hide My Email, more - 9to5Mac
During its WWDC keynote today, Apple unveiled a new iCloud+ service with new features alongside iCloud storage. iCloud+ includes three...
9to5mac.com
How to turn it off:
How to turn on/off iCloud Private Relay in iOS 15 - 9to5Mac
This detailed guide with screenshots covers how to turn on/off iCloud Private Relay in iOS 15 on iPhone and iPad as well as the pros and cons.
9to5mac.com