Top surgery would produce the result you want, if all you're looking for is flatness. There are multiple procedures to choose from based on your size and form, and some surgeons specialize or prefer specific procedures over others. More and more surgeons are open to doing this now than they were in the past. Some may still ask that you provide a referral from a mental health professional, as it is their job to confirm that you know what you're getting into.
But since you are not transgender, you should expect to pay out of pocket for it. It is a cosmetic procedure for you and not medically necessary. I'd budget around $10k for everything.