When you add DoorDash or any other third party delivery service into the equation, you add two more parties to this - the service itself, and the driver, who is usually an independent contractor.
What this has led to in my experience is that when something goes wrong, instead of me working it out with the restaurant, I am left frustrated, hungry, and hung out to dry by three parties - the restaurant, the platform, and the contractor.
If you read enough of the DoorDash subreddit[1], you realize that a tip is not a gratuity for good service, it's a bid for an independent contractor to take up your delivery. However, you have no ability to choose which Dasher takes it, and they are under no obligation to represent you as your agent or look out for your interests. So if they show up and the food is cold, not their problem, they get the tip because they accepted the bid.
When DoorDash had a major outage some time back, I had placed an order for about $70, generous tip (because I realize it's really a bid) and fees included. My order was prepared and ready for pick up just as the whole platform went down. It was impossible to cancel my order, because DoorDash was down, so I made alternate arrangements for dinner and figure I'll reach out for a refund when things are back up.
About three hours later, I get a notification that my order is out for delivery. The optimist in me hoped that the restaurant saw that some food sat out in the "danger zone" for several hours and remade it, or that the Dasher realized that the containers weren't the slightest bit warm, or something like that, but nope. I got dropped off a lot of food that was beyond safe to eat, not even worth saving to have as leftovers for a later meal, and now I have to dispose of all of it.
When I finally got through to support later that night, I asked for a refund, and they said they could only give me a credit for the meal, not the tip. I said I want the whole order refunded to my original payment, they said well, here's a credit and it will convert over to that later. One week and several phone calls later, they stopped telling me it was "too late to get a refund" and I got my refund and uninstalled the app. I don't need that negative energy in my life.