If you need to use CDATA in feed, you may need to replace symbols with HTML codes, e.g.:

This will be outputted in your feed something like:

<![CDATA[Some Product Title]]>

If you need to include shortcode in tags double quotes, use:

This will be outputted in your feed something like:

<item id="123"></item>

If you have some specific requirements, you can also create your custom shortcodes to be used in feeds. For example try putting this to your (child)
theme’s functions.php file:

add_shortcode( 'alg_product_price_multiplied_by_stock', 'alg_product_price_multiplied_by_stock' );
if ( ! function_exists( 'alg_product_price_multiplied_by_stock' ) ) {
function alg_product_price_multiplied_by_stock( $atts ) {
$product_id = get_the_ID();
$product = wc_get_product( $product_id );
if ( ! $product->is_in_stock() ) {
return 0;
} else {
return $product->get_price() * $product->get_stock_quantity();
}
}
}

Now you can use it in your feed like:

<stock_price>[alg_product_price_multiplied_by_stock]</stock_price>