Disables the PayPal gateway when the cart contains multiple items. PayPal disabled the ability to purchase multiple subscriptions in a single purchase.
<?php
/*
 * Plugin Name: Easy Digital Downloads - Disable PayPal for Multi-Item Checkout
 * Description: Disables the PayPal gateway when the cart contains multiple items. PayPal disabled the ability to purchase multiple subscriptions in a single purchase.
 * Author: Sandhills Development
 * Author URI: https://easydigitaldownloads.com/
 * Version: 1.0
 */

function pw_edd_disable_paypal_on_multi_item_checkout( $gateways ) {
	
	if( edd_is_checkout() && count( edd_get_cart_contents() ) > 1 ) {

		if( ! empty( $gateways['paypal'] ) ) {
			unset( $gateways['paypal'] );
		}
		if( ! empty( $gateways['paypalexpress'] ) ) {
			unset( $gateways['paypalexpress'] );
		}
		if( ! empty( $gateways['paypalpro'] ) ) {
			unset( $gateways['paypalpro'] );
		}

	}

	return $gateways;
}
add_filter( 'edd_enabled_payment_gateways', 'pw_edd_disable_paypal_on_multi_item_checkout' );
To implement this snippet on your site, create a brand new, empty WordPress plugin and paste the above code inside.