It's hard to find a Yandere character who doesn't overstep boundaries and consent because the point of Yanderes is that they ARE overstepping your boundaries and consent. They literally kidnap, stalk, drug and murder your loved ones. The Yanderes that are doing that are just staying true to their title, there's no such thing as a "good" or "green-flag" Yandere. It just doesn't exist.