I'm looking to find a way to lock down the wiki the same way you have here, but I can't figure out this Wiki code stuff. In fact its so confusing I can't figure out how half the things have been done here. All I managed to do was tweak up the theme so far, if you can help me figure out some things. I wanted to make it so no one can add or edit pages without being authorized to do so.
Yeah wiki code is super user unfriendly, Google is your best friend for finding how to do stuff. If I'm honest one of the general Fandom admins seems to have added that lock through some custom code that I can no longer find, but you can put locks on individual pages which is a bit more tedious. Look into disabling anonymous editors.