Trevorrow’s script did nothing to ever answer that question. JJ returned and found an answer that fit beautifully with both existing films. When you look at the details of the stories, nothing in TROS conflicts or contradicts or rewrites anything in TLJ.
Totally disagree about the latter, but, and not that that’s flawless, DOTF absolutely does answer that question, although it retcons TLJ, as does TROS. Also, TLJ answers that question.