'Spot reduction' doesn't work — here's why
The idea that training abs melts fat specifically off your stomach is incredibly persistent — and it just doesn't hold up physiologically. When a muscle works, it pulls energy mainly from the bloodstream and its own glycogen stores, not from the nearest layer of subcutaneous fat. Fat loss happens systemically, in an order largely set by genetics and hormonal profile, not by which muscle you just trained.
Studies where people trained only one side of the body (say, one arm) for several weeks found equal fat loss on both sides, despite only one being trained. That closes the 'spot reduction' question pretty clearly.
What actually works is an overall calorie deficit plus strength training that preserves muscle while you lose fat. Train your abs for core strength, not fat burning — they'll show up once your overall body fat percentage drops.