WooCommerce adding product to cart programatically

I have checkbox that when clicked should add a product to the cart ans when unclicked should remove it.
Developer before me solved the problem using Fee’s which should be changed to product. He used

add_action( 'woocommerce_cart_calculate_fees', 'checkout_radio_choice_product', 20, 1 );

I think I got the code to work I am just struggling to find the right hook. woocommerce_add_to_cart is not the right one. Can anyone point me in the right direction?

function checkout_radio_choice_product()
{  
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    $mp = WC()->session->get( 'magic_product' ); //true or false
    
    if( $mp) {
         $product_id = 11446;

        $found = false;

        //check if product already in cart
        if ( sizeof( WC()->cart->get_cart() ) > 0 ) {
            foreach ( WC()->cart->get_cart() as $cart_item_key => $values ) {
                $_product = $values['data'];
                if ( $_product->id == $product_id )
                    $found = true;
            }
            // if product not found, add it
            if ( ! $found )
                WC()->cart->add_to_cart( $product_id );
        } else {
            // if no products in cart, add it
            WC()->cart->add_to_cart( $product_id );
        }
    }
    else {
        WC()->cart->remove_cart_item( $product_id);
    }
}

Answers:

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Method 1

Got it to work using woocommerce_before_calculate_totals hook

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