From iOS16.4, iOS needs to enable web inspector explicitly,

if #available(iOS 16.4, *) { 
    webView.isInspectable = true
} 

Defaults to false.

Set to true at any point in the view’s lifetime to allow Safari Web Inspector access to inspect the view’s content. Then, select your view in Safari’s Develop menu for either your computer or an attached device to inspect it.

https://developer.apple.com/documentation/webkit/wkwebview/4111163-isinspectable

discussion