Deactivate subscription specific variation - Woocommerce + All Products for Woo Subscriptions

Question

I'm using Woocommerce + All Products for Woo Subscriptions to sell subscriptions.

Some of my products are variable (Attribute : Conditionnement) :

• 1 => Echantillon
• 2 => 100g
• 3 => 200g
• 4 => 500g

I want to deactivate subscription only for the first variation (echantillon) on different products.

Already tested this code from @mujuonly here : WooCommerce Subscriptions: Hide one variation subscription

add_filter('woocommerce_subscription_variation_is_purchasable', 'conditional_variation_subscription_is_purchasable', 20, 2);

function conditional_variation_subscription_is_purchasable($purchasable, $product) {

    $check_attributes = [
        'attribute_pa_conditionnement' => 'echantillon',
    ];

    $matching_variation = find_matching_product_variation_id($product->get_parent_id(), $check_attributes);
    if ($matching_variation == $product->get_id()) {
        $purchasable = false;
    }
    return $purchasable;
}

function find_matching_product_variation_id($product_id, $attributes) {
    return (new \WC_Product_Data_Store_CPT())->find_matching_product_variation(
                    new \WC_Product($product_id),
                    $attributes
    );
}

Not working at all for me.

Echantillon already available even with snippet