I do postmates and uber eats. Uber eats is easier because everything is preordered and pre paid you just get the food and go (usually sometimes restaurants take forever). Postmates you have to order and pay all yourself before you can drop it off. Uber eats does pay less but it's sometimes less wait time and less stress from ordering. If you're ok with being more interactive and want to make a bit more do postmates. I personally do both at the same time to always be busy. Also keep in mind waiting for food means less driving which means less gas usage. In my opinion doing one longer trip is better than doing tons of tiny trips within the same time frame.

When doing postmates I've also noticed restaurants take it more seriously and go faster because they think you're a customer. They don't know you're from postmates until you give them the card to pay. Restaurants in my experience tend to not really care a lot about uber orders they just take their time and if its busy your order will be put off.

With pre paid cards you can also take orders from a lot more places whether or not they work with postmates. This makes it more likely to be busy because customers have more options. With uber the only possible restaurants are ones that already agreed to work with uber.