I actually worked as a delivery driver for a local competitor for Uber eats back in college. In that case, it was pretty much all parties that were getting screwed. Restaurants gave up some of their profit margin, delivery personnel worked for poor wages and paid for their own equipment, and the customer paid a hidden markup on all items.

I started before they cranked up the exploitation and quit as the terms got increasingly bad.

I don't even think they ran a profit at that point, so I guess everyone was getting screwed