It should just be a set of protocols.
1) Your domain has a dns op (order placement) record like an mx record. Your op record points to your online pos system. A standard chunk of data is sent by the customer browser and received by your system.
2) You pay a company for marketing+online menu services. You optionally grant them the right to list/crosspost the same data on competing services. You have the choice which menu-fronts are allowed to use your name and advertise your product.
3) The order comes into your system like any other order. This triggers a separate signal to a p2p dispatch network. The dispatch network load balances all the incoming orders, assigning them to drivers in a logical way that hits restaurants and destinations with minimal extra travel.
4) The delivery driver chooses any client they want, that is compatible with the dispatch network. Tasks are routed to their client.
The order placement, pos, and the dispatch network are totally separate technologies, not proprietary vertically integrated institutions.