Experts seem to occur at an intersection between personal interests and professional experience. Would they continue to do this work for free if they didn’t need the paycheck? So, go where the hobbyists are and talk to people. Then evaluate those people against published work whether products or writing and whether professional or personal then evaluate that published work against industry norms on the basis of expenses and utility.
I understand that is a lot of effort, but it’s what separates the actual experts apart from people who are just good at merchandising themselves.