Taxonomies don’t show up on in the dashboard page for a custom post type in wordpress 5.22

Question

I’ve pasted your code in Twenty Nineteen and it works as expected with Classic Editor ( and I’m sure it will work pre-Block Editor also ). Your taxonomy will not show up in the Block Editor unless you specify to display that taxonomy in rest as you’ve done with your post type:

register_taxonomy( 'product-category', 'product', array(
    'hierarchical'=>true,
    'label'=>'product categories',
    'show_in_rest' => true
) );

Once you enable REST it will become available in the Block Editor.