(1) Drivers are paid in 2 factors, a tip provided by the user, and a per delivery fee provided by doordash thats variable, and generally in the industry is between 10 and 20% of the basket cost
(2) doordash additionaly guaranteed a total "minimum compensation" per delivery up front that was like ~20% of the cost of the basket
(3) Doordash would use the tips users paid to offset the amount they would pay drivers in order to meet the "minimum comp guarantee", so if you ordered 100 dollars in food, and tip 20 dollars, and the minimum compensation on the order was 20 dollars,doordash would pay the driver nothing, and your whole tip would sub for driver pay. If instead you tipped 0 dollars on your 100 dollar basket, doordash would pay the driver 20 dollars out of its own funds to meet the minimum comp. Likewise if you tipped 10 dollars, doordash woud pay 10 dollars.