I’ve flown with a dog of similar size multiple times as a pet in cabin (paid, not an ESA). Nobody has ever weighed my dog, asked for his weight, or even measured my bag. I usually use one of the Sherpa bags that has a Delta logo on it, but mine has no wheels.

As long as you pay the fee and the bag fits under the seat, I would not anticipate any problems. If the wheels on your bag make it look larger than other pet bags, mayyyybe an extra vigilant agent would measure it. But as long as you’re within the guidelines on the Delta website, you should be fine.