Woocommerce Adding price amount class ("woocommerce-Price-amount amount) to return $price

I am building a measurement Store with Woo and need some special Outputs for Pricing I am not able to fix.

The Price Output needs to be:

Price per Package and the Price per Unit so I need to add the class="woocommerce-Price-amount amount" for Display

1) I had used this Snippet to Display the Unit of Package Price:

function cw_change_product_price_display( $price ) {
    $price .= ' per package';
    return $price;
  }
	add_filter( 'woocommerce_get_price_html', 'cw_change_product_price_display' );
	add_filter( 'woocommerce_checkout_cart_item_quantity', 'wb_checkout_review', 10, 3 );

2) And tried these to adding the woo Price Amount, resulting into crashing.

add_filter( 'woocommerce_get_price_html', 'wb_change_product_html' );

function wb_change_product_html( $price ) {
    $price_html = <span class="woocommerce-Price-amount amount"> ' . $price . ' per m² </span> ;
    return $price_html;
}

I Cant find a $price amount var. or table so I don't know how to fix these. I hope someone is able to help me with these to fix.

Thanks a lot