To help with events happening virtually, in GigPress 2.3.25 we have introduced a filter that will allow you to set the City field to not required.
Here is a sample snippet that shows you how to do that. This snippet can be placed in your theme’s functions.php file or in a custom plugin. (You can find more about that in this article.)
add_filter( 'gigpress_venue_city_required', '__return_false' );
And that’s it. 🙂