Same issue here.
Big Sur 11.4
Safari 14.1.1
Xcode 12.5
Also tried with Safari TP 124 but I see the same behaviour.
I tried with a couple of devices on 14.6 and multiple simulators even with older iOS versions, is not only a problem of WKWebViews inside apps, even sites opened in Safari on iOS cannot be inspected.
It is working on an old Mac I was able to access for a test with Safari 13.1, macOS 10.15.7 and Xcode 12.2
gualtierofrigerio
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