There's a company called EatSure that already does this. I think they target food courts in shopping malls, because the restaurants are as close as can be.
The delivery times weren't great when I ordered from them. But weather it was because they have fewer delivery partners or weather trying to get delivery from a mall is a pain ( hard to find parking right outside, parking in the basement park is chargeable ) then the delivery partner has to go up to the top floor of the mall, try to get the food ( among the rush especially during the weekends).
You could work on clustering nearby restaurants together and allow orders from them, but it's just not that viable and you'll just be burning money trying to take market share from swiggy and Zomato.