The oneness is right here, it is hidden in your very question, but you are missing it. Allow me point you to it directly:

“If we cut our hand, only we will feel so where is the oneness there?”

There it is! There’s your oneness - “only you”. And this is entirely correct.

If only you will feel the pain, then only you exist for you. If you can’t feel anyone else’s pain, then what are you experiencing? Yourself. What have you always been experiencing? Yourself. What have you ever known, and ever will know? Yourself, yourself, and only yourself.

You cannot know or experience none other than yourself, it is not possible.