The restaurant probably sets that price. Not only do delivery services ask for fees and tips from you, the customer, they will also take 20% of the restaurant’s earnings for using their delivery services. Hence why some restaurants still choose to be on the app for visibility but have higher prices and/or separate delivery and pickup services that they set at normal prices and prefer the customer use instead.

Learned this when I was working for a delivery start up that operated locally and didn’t charge such a fee.