If you don’t like a video you should just swipe away because the algorithm is looking for engagement and even though disliking it is negative it is still engagement and it will cause YouTube to show that content to more people. It can use your dislike to determine if that video is good or not for people similar to you, so your dislike might change who it is suggested to, but it won’t cause it to be suggested less. At least that is what I have heard, I don’t know if that is actually true.