Redirect to Shop or any page if the Cart is empty.

functions.php

/* 
* How to add the custome code. 
* 
* Please follow below instructions:
* 1. Copy the below code.
* 2. Open your child theme's functions.php file.
* 3. Paste the copied code at the very bottom of it & save the file OR upload it on your server/hosting.
*/

add_filter( 'template_redirect', function (){

	if( ! is_checkout() ){
		return;
	}

	if( WC()->cart->is_empty() ){
		wp_redirect(wc_get_page_permalink( 'shop' ));
	}
} );