Same problem, Big Sur 11.4, Xcode 12.5.1, Safari 14.1.1, iOS 14.6. I've successfully debugged on my iPad using Safari on my iMac (should be all of the same version numbers involved), but right now, using my MacBook Pro and my iPhone, I've got nothing but the three blank tabs.
Silent3
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
From
New Hampshire