title tag for custom post type remove taxonomy name from title tag

I believe that WPPizza Categories is coming from

'name' => _x( 'WPPizza Categories', 'taxonomy general name' )

And your url problem is coming from not setting a slug. For example:

'rewrite'   => array( 'slug' => 'pizza_categories', 'with_front' => false ),

You need to replace the slug with something else, as you need something in place of ‘wppizza_menu’ in the url. You can change the title in your page template if you just want to remove ‘WPPizza Categories’, otherwise change the general name and it should propagate to the title tag.

I’d recommend using a regex and get_the_title(); if you want to remove the taxonomy name completely.