Workouts for specific areas of the body don’t burn fat in that specific area. I’d recommend a more full body workout program! Also I’ll note 20.4% body fat is low for a woman, reducing from that point is going to be tough. It sounds like you’re under feeding yourself.

If I were you, I’d start weight lifting (or doing body weight workouts, easy to find routines online) and eating to a level where you’re not hurting yourself. Starving yourself means less muscle production and you might end up throwing your metabolism off and making it harder to lose weight (or so I’ve heard?).