"What is the difference between the speed and the car?"
The car is a thing, like your body. The speed is what the car is doing, like your mind is something your brain is doing. No problem, nothing to accept.
My own mind is something I am doing, just as I am typing just now. It should be obvious enough that neither is something you are doing.
"Causation" is purely interpretation; the universe has nothing to do with that. People invented causation to help understand the universe, but there is nothing fundamental about it. So long as you think you need causation of any kind to understand consciousness, you will get nowhere.
The car is a thing, like your body. The speed is what the car is doing, like your mind is something your brain is doing. No problem, nothing to accept.
My own mind is something I am doing, just as I am typing just now. It should be obvious enough that neither is something you are doing.