If you want to be a criminal policeman, you don't really need self-defense. You just need to learn how to hit the master when the criminals catch him or fight. In fact, there is nothing to learn. It's no use. You just need to study hard and master it. Whether it is arresting people or self-defense, it is absolutely suitable for you. Judging from your height and your comprehensive data, you are suitable to be an athlete, but since you want to be a policeman and have logical thinking ability, Sanda is generally used to beat others, but the police can't beat people. Taekwondo can keep you fit. I suggest you learn to capture and wrestle. .

I hope my answer will be acceptable to you.