How to effectively remove an item from the cart on shopware 6

Hello i am trying to prevent products with different properties from been mixed up in the cart.

to do that I have set some conditions and displaying some notices to the user on the cart. but I need to be able to remove items that I make a notice about.

at the moment, i am setting up logic

public function onLineItemAdded(AfterLineItemAddedEvent $event): void
    {
        $lineItems = $event->getLineItems();
        $shipperExists = false;
        foreach ($lineItems as $lineItem) {
            $this->processCustomFields($lineItem);
            if (isset($lineItem->getPayload()["customFields"]["dropper_"])) {
                $shipperExists = true;
            }
        }

        if (!$shipperExists && isset($this->customFields["dropper_"])) {
            $this->flashBag->add(
                "info",
                "Invalid entry, You are trying to include a product without dropshipping option to a product with a dropshipping option."
            );         

        }

        if ($shipperExists && !isset($this->customFields["dropper_"]) && isset($this->customFields)) {
            $this->flashBag->add(
                "info",
                "Invalid entry, You are trying to include a product with dropshipping option to a product without a dropshipping option."
            );
        }
    }

and i then tried to use a cartservice

use ShopwareCoreCheckoutCartCartService;

$cart = $cartService->getCart($contextToken);

$cart = $cartService->delete($cart, $lineItemId, $context);

but i am unable to delete the cart item, please help