Remove slug from Custom Post Type in Wordpress

cpt.php

<?php 
/*
    *** You van use dash-icons https://developer.wordpress.org/resource/dashicons/
*/
add_action( 'init', 'register_cpts' );

function register_cpts() {
	register_post_type( 'services',
		array(
			'labels'            => array(
				'name'          => 'Services',
				'singular_name' => 'Services',
				'menu_name'     => 'Services'
			),
			'public'            => true,
			'show_ui'           => true,
			'show_in_menu'      => true,
			'supports'          => array( 'title', 'editor', 'thumbnail', 'excerpt' ),
			'has_archive'       => false,
			'rewrite'           => true,
			'hierarchical'      => true,
			'show_in_nav_menus' => true,
			'capability_type'   => 'page',
			'query_var'         => true,
			'menu_icon'         => 'dashicons-lock'
		) );
	
	register_post_type( 'locations',
		array(
			'labels'            => array(
				'name'          => 'Locations',
				'singular_name' => 'Locations',
				'menu_name'     => 'Locations'
			),
			'public'            => true,
			'show_ui'           => true,
			'show_in_menu'      => true,
			'supports'          => array( 'title', 'editor', 'thumbnail' ),
			'has_archive'       => false,
			'rewrite'           => true,
			'hierarchical'      => true,
			'show_in_nav_menus' => true,
			'capability_type'   => 'page',
			'query_var'         => true,
			'menu_icon'         => 'dashicons-admin-site-alt3'
		) );
	
	if ( defined( 'WP_DEBUG' ) && true !== WP_DEBUG ) {
		flush_rewrite_rules();
	}
}

add_filter( 'post_type_link', 'sl_custom_post_type_link', 9, 3 );

function sl_custom_post_type_link( $permalink, $post, $leavename ) {
	if ( ( ! gettype( $post ) == 'post' ) ) {
		return $permalink;
	}
	switch ( $post->post_type ) {
		case 'services':
			$permalink = get_home_url() . '/' . $post->post_name;
		case 'locations':
			$permalink = get_home_url() . '/' . $post->post_name;
			break;
	}
	
	return $permalink;
}


function sl_cpt_post_names_to_main_query( $query ) {
	// Bail if this is not the main query.
	if ( ! $query->is_main_query() ) {
		return;
	}
	
	// Bail if this query doesn't match our very specific rewrite rule.
	if ( ! isset( $query->query['page'] ) || 2 !== count( $query->query ) ) {
		return;
	}
	
	// Bail if we're not querying based on the post name.
	if ( empty( $query->query['name'] ) ) {
		return;
	}
	
	// Add CPT to the list of post types WP will include when it queries based on the post name.
	$query->set( 'post_type', array( 'services', 'locations' ) );
}

add_action( 'pre_get_posts', 'sl_cpt_post_names_to_main_query', 10, 3 );