How to prevent competitors copy my listing ?

I am a niche seller and I always find for niche with few competitors. But recently I have a competitor keep copying what I sold. He literally copy all the ideas from my listing. I can see every months he creates new product similar to my existing one. I am sure he is monitoring what I sold.

I spend most of my time do my product research. I dont want someone try to steal the hard work from me. However, I cant find any ways to hide my listing from him or report this behavior. What else can I do ?