I am an independent researcher (a term which I am well aware is often used as camouflage by "cranks"), currently looking for a PhD program suitable for skeptical people in their mid-50s. I also work part-time as an existential coach. My main interest in "indigenous" psychology is in the psychological diversity within "Western" cultures. You don't have to go to the jungles of a remote Pacific island to find people who are surprisingly different from Americans.
I'm not sure what I can bring apart from a willingness to ask awkward questions of those in charge of the status quo (warning: any status quo). If you haven't already seen it, this article https://thewinnower.com/papers/a-critical-examination-of-the-u-s-army-s-comprehensive-soldier-fitness-program has a few more awkward questions.