Did you read the manga? Naruto didn't go RSM, Kurama was anxious for action and took over for him. That's why Naruto said to him "Don't go nuts", and he wanted to ensure Sarada and ChoCho are safe with the actual him, no clones.Onion is far too weak for sasuke. He can push sasuke 3t though with ms
Onion pushed naruto to go rsm, and naruto confessed his clones are not strong enough to protect salad and chocho
Onion is about high kage level