What did Jesus mean by asking us to cut off our right hand, etc., if it causes us to sin?
It is not literal. Jesus was using exaggeration/hyperbole to make a point. It’s similar to when people say, “I’m so hungry I could eat a horse” or “I’d give my left arm for that.”
Jesus’ point was simply that we need to make a serious effort to avoid sin and keep our focus on things that are eternal rather than passing.