SME and fact checking - how does it work?

Recent Google updates have placed a greater emphasis on subject matter expertise (SME). Sites demonstrating SME are rewarded in the search rankings.
As a gambling expert (math/strategy/responsible gambling), I came to be more and more asked for fact-checking existent articles in gambling websites. I assumed (and heard) that SME doubled by fact-checking counts more in the algorithm of ranking.
As a non-expert in SEO, I am trying to figure out how the fact-checking criterion actually works from Google’s perspective. While checking for the author’s expertise seems to be an easy task (just a simple search and checking for their names on Wikipedia, Worldcat, etc.), when combining authorship and fact-checking we start from the assumption that the author is not an expert and the fact-checker should actually be the expert. This raises several technical questions. For instance: Is there any required formatting of the authorship line for Google to take the data as input for their algorithms? Or: How does Google make the association automatically between a certain topic and the required expertise? How they make the difference between experienced players as authors for instance and gambling theorists?
As a final remark, SME and fact-checking undermine the role of the AI in regard to writing.

Now how does that sort of SME verification actually work. I can imagine anyone can put anyone's name on any content and have it link to their soc. media profiles, wiki pages and whatnot.
Logically, I guess if an article links to some SME's, for instance, linked in profile, the profile should then link back to the article to verify actual affiliation with that content. However even in that case, it is too much of a longshot to treat that as a significant ranking factor.