You need more options.

These are not the droids you are looking for...

If our consciousness ends when we die (and it seems that way), that implies that our consciousness is generated by our brains. It seems kinda like a projector projecting an image on a screen. There is some scientific thought that somewhere along man's evolution a "mirror" axion or dendrite may have developed in our brain.
With regards to happiness, we are happy when our body "feels" happy. This is affected greatly by having the correct amount and types of hormones and chemicals in the brain like Serotonin and Dopamine.

Noy enough I can assure you of that.

Who are "we" if not our minds...?

I think that conscious awareness is the only thing about our reality that is NOT an illusion. I think that Sam Harris is an illusion.

I agree that a material brain can not give rise to consciousness, but all our experiences are framed by conscious awareness nevertheless. If, according to our world view we ought not be conscious but we are conscious anyway, there must be something wrong with our world view.

Thoughts and conscious awareness are two different things. Thoughts are of the body and require no conscious awareness. Some super-conscious people can control their thoughts almost 100% while others have no control.

I believe that once we can finally channel all of our mental energy on one thing then we can say that we’ve achieved more than 20%

I don't know that I can put a percentage on it, but we have less control AND precision in our thinking than we generally suppose that we do.

Some, however that's ignoring the paradox you're skirting. What do you consider "control"? Your mind is designed to control your body, your conscious mind can perform repetitive actions to alter your subconscious mind.

The way I'd look at it is through Artificial Intelligence. Some scientists define AI as the ability to mimic humans but others define it as the ability to truly rewrite its own code. I'd say that true control over your own mind is the ability to rewrite the way it works, therefore your ability to do things like build or change habits, heal emotionally, or learn are all forms of control over your own mind.

However I'd put our current abilities far beneath 20%.

0% We do not control our minds. We have some voluntary direction of some of our faculties.

Sam Harris is not the only one that says this. btw who the hell is Sam Harris? (jest)

My best answer would be: I don't know.

We seem to have some control, at least more than say a dog, cat, or chimpanzee. However, I can't sit still, close my eyes, and think of nothing even for 1 minute. I suppose, the reactions in the billions of neurons in our brains involve quantum mechanics " spooky action at a distance". This implies that our "free will" is affected by randomness. We know that happenings when we are young are embedded in our brains and affect our outlook and decisions when we are older. We also know that damage to our brains can result in changes in our behavior, like the guy that murdered his family and was later found to have a brain tumor that altered his thinking. Our behavior and our thinking is affected by our environment. My feeling of consciousness is an illusion. Additionally, thousands of scientific experiments have been run to find evidence of a soul existing. No evidence has ever been found, so far.