Iirc, Su Luxia’s plan is to make the FL realize how horrible the ML was to her by treating him the way he treated the FL. Seeing the person she loves be hurt the same way he had hurt her, she should start to see how horrible her situation actually was instead continuing to be blinded by love. Often times, victims of abuse don’t see it or even acknowledge it as abuse (especially if the person abusing them is someone they love and care about) until it is directed towards someone else.
Ludwig strikes me as not particularly bright. He's already proven that if he can't solve a problem with brute force he has no idea how to deal with it.