Going back to Jakku would let them explore who Rey’s parents were. Are they really dead? Really nobodies? But I think Jedha would make more sense in terms of the saga. If Rey isn’t a Skywalker, her parentage is of no importance.
I was perfectly happy with the reveal of Rey’s parents being nobody case closed, move along. If they keep insisting with this nonsense then fuck this movie.
Kylo could be lying. But my guess is if they do anything, they will be revealed to be no-one connected to any family previously in the saga (aka nobodies) but they might be significant in other ways and in any case, they were significant to Rey as they were her parents. But to assume Kylo was not lying in some way (the best Sith lies have been shrouded in truth but used to forward their own agenda) is a mistake.