I can tell you guys that this issue is only related to all Xcode versions from 16.0 to 16.2 !! I downloaded Xcode 15.4 and managed to run it and i can download runtimes no problem !

Here is what happen with Xcode 16.0 to 16.2 ! Hope you can fix the issues soon :(

Other people are having same issue ! https://developer.apple.com/forums/thread/771499

same problem as well i created a post here : https://developer.apple.com/forums/thread/774890?login=true&page=1#829374022