This is one of the easiest deals. Just use Future card to pay for NYC Subway and you get points equivalent to 100% cash back, as soon as your transaction posts - no need to wait for your statement to redeem.
Future Card works similar to cash app - load money and spend it using virtual card or physical card (this one will take about a week, so it’s best to start using virtual card to maximize your savings - you can add it to your phone’s wallet).