I think my title has made you confused because of two words "Best" and "Better". Ok, let me clarify that.
There is no SEO expert who could give you guarantee. But, they could give you probability. As the concept of probability, there is always a room to make better.
I will share a plan what is the BEST among the BETTERS. Now, I think you have got the point.
If you get any guarantee from other expert, then I think you should immediately contact with that expert.
I will not tell any special SEO plan but SEO logic what could make you gigantic on you niche.
The probability of getting success of my logic is 90%.
Before execute my plan, I will share why my logic works. I think that will help you to understand why I am the good fit on your business.