A Reylo type relationship required Kylo to be less evil in TFA and for Rey to join Kylo in TLJ. It’s infeasible to squeeze it into IX at this point with how the previous 2 films have been.
Well, they almost joined in TLJ, but if the story as a whole is supposed to end with them together that can’t happen before the last movie. Romantic stories usually has some kind of trouble in the middle that is overcome by the end, so it could happen in IX. Of course Kylo has done some unforgivable things, but I would say things are pointing toward some kind of redemption in the end which would make a Reylo relationship of some kind more “okay” even though it is of course problematic in many ways. But that’s what makes it interesting as well, it’s not obvious what will happen and how it will be dealt with.