This has been done/presented numerous times before and AFAIK, there are a few websites in operations providing the same service.
I see an example
here but this is not what I was thinking exactly.
Why would you want to put all the efforts into creating a platform when you can literally have a discord server, a trusted escrow with minimal escrow fee, and someone to manage all of it? I mean you can start from this and if it's getting big, you can start with an actual website.
This way I and if I have a team will need to have touch in every point but my idea is everything in between the users. If any case comes for admin to involve then they will act as resolution team. I think this only possible if there is a complete web application.
To be honest, if you would have started a better App than Just-Eat, you would be successful. Just-Eat has a terrible UI and much worse business model. If I place an order from my phone directly to the restaurant, I sure can save a fiver.
I guess I lost my interest at the end so could not move forward.