Use the price including tax in the price attribute for the woocommerce product feed manager

Alter Product feed price item

/**
 * Alter Product feed item
 * Use the price including tax in the price attribute
 */
function alter_feed_item( $attributes, $feed_id, $product_id ) {
	global $product;
	$product = wc_get_product( $product_id );
	
	// show price including tax
	$attributes['price'] = $product->get_price_including_tax() . " USD";

	// IMPORTANT! Always return the $attributes
	return $attributes;
}
add_filter( 'wppfm_feed_item_value', 'alter_feed_item', 10, 3 );