wp-unregister-builtin-post-types-default-post-page.php

<?php

add_action('init', 'hwk_deregister_builtin_post_type');
function hwk_deregister_builtin_post_type(){
    global $wp_post_types;
    
    $unregister = array(
        'post',
        'page',
    );
    
    foreach($unregister as $post_type){
        if(!post_type_exists($post_type))
            continue;

        $post_type_object = get_post_type_object($post_type);

        $post_type_object->remove_supports();
        $post_type_object->remove_rewrite_rules();
        $post_type_object->unregister_meta_boxes();
        $post_type_object->remove_hooks();
        $post_type_object->unregister_taxonomies();
        unset($wp_post_types[$post_type]);

        do_action('unregistered_post_type', $post_type);
        
        $wp_post_types[$post_type] = new stdClass();
        $wp_post_types[$post_type]->show_in_menu = false;
        $wp_post_types[$post_type]->publicly_queryable = false;
        $wp_post_types[$post_type]->_builtin = false;
        $wp_post_types[$post_type]->name = false;
    
    }
}