Limit Post Views: Don't allow post views for certain categories.

my_pmprolpv_has_membership_access.php

<?php

/**
 * Limit Post Views: Don't allow post views for certain categories.
 */
function my_pmprolpv_has_membership_access( $has_access, $post ) {
    
    // Set blocked categories here.
    $blocked_categories = array( 'silver', 'gold' );
    
    foreach( $blocked_categories as $category ) {
        if( has_category( $category, $post ) ) {
            $has_access = false;
        }
    }
    
    return $has_access;
}
add_filter( 'pmprolpv_has_membership_access', 'my_pmprolpv_has_membership_access', 10, 2 );