Create Network option missing under Wifi for P2P ad-hoc networking (I'm a developer using Xamarin build host)
Enable/tick &quot;Show legacy networks and options&quot; in...
System Preferences &gt; Network &gt; Wi-Fi &gt; Advanced &gt; Wi-Fi (see image below)
...for the option to &quot;Create Network...&quot; to re-appear in the AirPort menu item.
See also: https://support.apple.com/guide/mac-help/mh11937/mac
https://support.apple.com/guide/mac-help/mchl98b9beb6/11.0/mac/11.0

PS/note: After pressing &quot;OK&quot;, it's easy to miss the &quot;Apply&quot; button.