Help with creating coupons programmatically

Hello,

For a project i am trying to create coupons programmatically with some data ( acquired points)

When i am trying to run it via a shortcode on a random page everything works expect the saving of the coupons.
When i try to save it with add_action(‘admin_init’, ‘userbyidtest’) it works but i don’t want it that way.
I really want it to work as a shortcode when i visit a certain page on this case. Can anyone have a look and help me out?

function userbyidtest(){
	
	$users = get_users();
	global $wpdb;
	global $woocommerce;
	$percentage = 10;

	foreach($users as $user){
		$usermail = $user->user_email;
		$userdname = $user->display_name;
		$userID = $user->ID;
		$totalpoints = $wpdb->get_var( "SELECT points FROM wp_wc_points_rewards_user_points WHERE user_id='$userID'");
		//COUPON SETTINGS
		$expdate = '20 days';
		
		if($totalpoints > 10){
			// COUPON SETTINGS 2
			$totaldiscount = ($percentage / 100) * $totalpoints;
			$mintotal = $totaldiscount * 4;
			
			
		
		
			
	$coupon = new WC_Coupon();

	$userdname2 = str_replace(' ', '', $userdname);	
	$userdname2 = strtolower($userdname2);
	$coupon_code = $userdname2 . '-' . $totaldiscount . 'dc';
		
	$coupon->set_code($coupon_code);

	//the coupon discount type can be 'fixed_cart', 'percent' or 'fixed_product', defaults to 'fixed_cart'
	$coupon->set_discount_type('fixed_cart');

	//the discount amount, defaults to zero
	$coupon->set_amount($totaldiscount);

	//the coupon's expiration date defaults to null
	$coupon->set_date_expires(null);

	//determines if the coupon can only be used by an individual, defaults to false
	$coupon->set_individual_use(false);

	//the individual prodcuts that the disciunt will apply to, default to an empty array
	$coupon->set_product_ids(array());

	//the individual products that are excluded from the discount, default to an empty array
	$coupon->set_excluded_product_ids(array());

	//the times the coupon can be used, defaults to zero
	$coupon->set_usage_limit(1);

	//the times the coupon can be used per user, defaults to zero
	$coupon->set_usage_limit_per_user(0);

	//whether the coupon awards free shipping, defaults to false
	$coupon->set_free_shipping(false);

	//the product categories included in the promotion, defaults to an empty array
	$coupon->set_product_categories(array());

	//the product categories excluded from the promotion, defaults to an empty array
	$coupon->set_excluded_product_categories(array());

	//whether sale items are excluded from the coupon, defaults to false
	$coupon->set_exclude_sale_items(true);

	//the minimum amount of spend required to make the coupon active, defaults to an empty string
	$coupon->set_minimum_amount($mintotal);

	//the maximum amount of spend required to make the coupon active, defaults to an empty string
	$coupon->set_maximum_amount('');

	//a list of email addresses, the coupon will only be applied if the customer is linked to one of the listed emails, defaults to an empty array
	$coupon->set_email_restrictions($usermail);

	//save the coupon
	$coupon->save();
		
		
		
		}
	}
	
	
	
}
add_shortcode( 'userbyidtest', 'userbyidtest');
//add_action('admin_init', 'userbyidtest');