Niche based on my book

I am writing a book for accountants about how they are underutilizing their brain. I discuss 12 of the most common pain points that accountants experience and how to manage their minds to undo those pain points.

My funnel will be a free quiz based on the book and my coaching program will teach them how to manage their minds to deal with any of the 12 pain points. The coaching program is mentioned throughout the book.

My question is in regards to my niche for marketing purposes, should I be narrowing down the type of accountants I’ll market to? Public accountants that work for the Big 4 firms? Accounting entrepreneurs?

Or should I just market the book to all accountants and then have the book and the quiz be the filter for the program?