There are always exceptions and some people do thin naturally in the crown while maintaining a NW 2 hairline, however, this is very rare. I think hair restoration is at a point where it should look 100% natural. Unfortunately, most people just don't have enough density in their donor area to treat a thinning crown at a high density. But some patients do.
I am very selective about who I would choose to operate on my head. I advise you to consult with at least 3 doctors in person. In my opinion, you need to find a doctor who is ethical, artistic (hairline design) and extremely skilled. Price should be the last thing on your mind! For FUE, I like Dr. Mwamba, Dr. Bisanga, and Dr Lorenzo. The choice is of course yours, but all doctors are not at the same level.
Finally, I wouldn't worry about naturalness. If you choose an excellent doctor, this should be a non-issue. Most people would never be able to notice anything.
What is your NW level? How old are you?
Cheers!