Belly fat can be stubborn. What I would suggest besides diet is also exercise. Low-intensity exercise like running can be helpful but for your diet, we would recommend high protein, high fiber, and low-saturated fat diet.
It is going to take some time to get progress but consistency is key.
Here is an idea you can try: https://www.nutriliving.com/blog/7-ways-to-permanently-banish-belly-fat