1. Cart -> 2. Shipping Address -> 3. Shipping Option -> 4. Payment
NOTE: Our checkout flow is very similar to Shopify checkout in case you're familiar with that.
I'm trying to understand where in the checkout flow PayPal Checkout can fit in, in particular how we ensure the customer is able to choose an appropriate shipping option (e.g. next day vs standard vs international etc.) once they've selected their shipping address.
Shopify currently offers PayPal Checkout both on step 1 (Cart) and step 4 (Payment).
Adding PayPal Checkout to step 4 (Payment) seems pretty straight forward because we can use the shipping address captured in step 2 (Shipping Address) and pass shipping_preference: 'SET_PROVIDED_ADDRESS' when creating the PayPal Order, preventing the customer from changing their shipping address in PayPal Checkout -- this is critical as it ensures customers are unable to invalidate their shipping option by, for example, changing from a UK -> US shipping address.
However, if we wanted to add it to step 1 (Cart) or even directly on product pages (which Shopify also offers), I can't see how it would work as there doesn't appear to be a way to offer up different shipping options within the PayPal Checkout?