Unfortunately, currently it seems that we can only add the https://apps.shopify.com/dhl-packstation-2 app using the Shopify Plus plan because it requires Shopify Checkout Extensibility. For Checkout Extensibility, our store must be on the Shopify Plus plan. So you can’t use any features that are only compatible with Checkout Extensibility.
It is such a pitty that Shopify doesn’t support DHL pickup stations integration by default. This functionality very soon will become the 1st option for sending parcels. It is much cheaper (-20%), more convinient and more sustainable.