I'm wondering if it's possible to allow users to enter their payment details on my site and process the checkout without needing to redirect them to a Shopify hosted page? From my understanding, this is possible through the Checkout API if you create a Sales Channel, but my use case does not seem to fit the requirement of having the "intention and capacity to onboard several hundred Shopify merchants in the first year after launch“ since I'm just looking to process checkouts for one store. I notice the Storefront API has a mutation called checkoutCompleteWithTokenizedPaymentV3, and I'm wondering if this could be used for completing a payment on an external site without creating a Sales Channel. Any guidance or suggestions would be very much appreciated!
I do not know of a way to have Shopify process the payment outside of the store's website (doesn't mean it's not possible though). But yes, I imagine Stripe would be the easiest route here.