Add custom value to datalayer

Hi

I tried to add an extra datalayer:

function my_product_filter( array $eec_product, string $ecommerce_action ){
// add an attribute only on product detail pages
	if ( $ecommerce_action === "productdetail" ) {
		$eec_product["dimension1"] = "Hello World"; // set a product scoped custom dimension
	}

	return $eec_product;
}

add_filter( 'gtm4wp_eec_product_array', 'my_product_filter', 10, 2 );

But I cannot see it in the console when checking the page using adswerve chrome plugin.
Eventually I wanted to add the product ID to the SKU like:
“sku” => “theSKU_theProductId”
Example: “93DKus_367865”
instead of “93DKus”
because my fb sync plugin transfer products as “theSKU_theProductId”.
So my retargeting dont match the sku from gtm4wp right now

I hope you can help ??