I have yet to meet any contributor to the site who regularly marks undergraduate essays, in one of the humanities fields. That kind of person would surely be able to supply useful information as to what is accepted, and what is not, as 'correct' English grammar. after all one definition of 'correctness', in our variegated search for it, must be 'that which is accepted by examiners and others in universities etc'. Whilst the OED is a help, so much of it is archaic.
I think that the quest for a single person to dictate the rules is misguided. Instead, I believe it will be more practical for you to study the concept of prescriptivism vs descriptivism.
Before I began participating on this site, I had no awareness that such a distinction existed. None of my totalitarian English teachers had ever let slip that rules are not universal truths. They simply meted out what is right and what is wrong, and woe unto the student who dared to defend his "improper" grammar.
The reality is, what is "correct" is sometimes debated between prescriptivists, and often subject to change. What is "correct" today may not be the standard at some time in the very near future. One good example of this is "the death of "whom." It is widely believed by descriptivists that the rule for usage of who vs whom is on its deathbed (and I tend to agree.)
I don't want to bog down this answer with too many words, because I would really like to have you read this blog post. I sincerely believe that it will be helpful to you.
I daresay there are several of us.
I myself have been out of the education racket for decades; but from the age of 12 until I left for college, I regularly marked undergraduate English papers for my father (it was his way of teaching me what he called 'practical grammar'), and I taught university-level theatre history and criticism for some years in the 1970s.
The canons here prohibit proofreading; but if you stand in need of it, I will be happy to point out—or, if you prefer, to correct, silently—any deficiencies of language and argument I notice in your posts.