Tips on finding experts on a specific topic
What you are looking for might better be identified using a bibliometric search rather than a typical literature review. Bibliometrics search and analyze metadata related to scholarly publications more than the actual contents of the studies. In your case, the metadata that you are interested in is identifying the leading authors in certain topics of interest.
A colleague of mine published an article that shows how to identify the most relevant literature using free bibliometric tools such as VOSviewer. That is, by beginning with a topic search on a citation database (e.g. Scopus or Web of Science), you can identify the most relevant body of literature, authors, schools of thought, etc. based on cocitations and other bibliometrics:

Walsh, I., &amp; Renaud, A. (2017). Reviewing the literature in the IS field: Two bibliometric techniques to guide readings and help the interpretation of the literature. Systèmes d’Information et Management. Retrieved from https://www.researchgate.net/publication/316560668_Reviewing_the_literature_in_the_IS_field_Two_bibliometric_techniques_to_guide_readings_and_help_the_interpretation_of_the_literature

You can get the article by following the link. It should set you on the right track.