I know there have been edits where Luke doesn’t die at the end of TLJ, but there’s really no way to explain his absence in IX if he is actually alive still. The effort might be to try to improve his characterization, but I think it would actually make him look worse. And can’t shoot or cgi new scenes with Luke in any feasible way. Maybe you could put TLJ scenes of Luke into TROS, but I don’t think it would be very seamless.

I think the fixation on lineage and bloodline is exactly why I personally felt she didn’t need to be related to anyone.