I had the same problem after I installed Xcode 14.0. On my swiss keyboard / is obtained with the combination ⇧7.
I fixed it thus
in the new Ventura System Settings - Keyboard - Keyboard Shortcuts - App Shortcuts I unchecked All Applications - Show Help menu, no big loss since I can access it from the toolbar
Xcode - Settings - Keyboard Bindings, the checkbox Adapt to current keyboard was checked, and I left it checked
in Xcode - Settings - Keyboard Bindings - Editor Menu for Source Code I selected Structure - Comment Selection and recorded the combination ⇧⌘7
the recorded combination is displayed as ⇧⌘/
now the block comment toggle works in my Xcode editor
Crosscheck
I went back to the first step above, and checked All Applications - Show Help menu; this overrode immediately my settings in Xcode, so I left it unchecked.
HTH