On the contrary, street dance is easier to learn now, and the requirements for dance skills are not very high, which can be said to be more popular. So, I suggest you learn street dance.
Besides, you said that your waist is not very flexible. Well, you'd better pay more attention to your waist at ordinary times. You usually have free time and practice waist exercises more, because whether it is national dance, ballet, Latin dance or street dance, the requirements for your waist are actually quite high, and the legs and waist are the most vulnerable parts for dancers. The waist supports the dancer's whole upper body, so before practicing any dance, we should first protect the waist and legs, and usually do more leg stretching and relaxation exercises. Especially after each dance, you must relax. )