HA - "what resources do you recommend I look into to find people taking a more rigorous approach to understanding the phenomenon of human morality"

If you're interested in the empirical phenomenon, I'm the wrong person to ask. (Maybe start with the SEP on moral psychology?) But on a philosophical level I'd recommend Peter Railton for a sophisticated naturalistic metaethic (that I respect a lot while not entirely agreeing with). He has a recent bloggingheads diavlog, but you can't go past his classic article 'Moral Realism' [here if you have jstor access].