I touched on it in my TROS Part 2 vid, but it was a jokey-joke because saying things about TLJ can be a bad time. Here's the thing, if the Emperor being alive now, ruins Anakin's sacrifice for you, you might have misunderstood the point of that sacrifice.https://youtu.be/J9F7_h4CAJM
That's the problem with the 2nd evil space wizard or the resurrection. 1 can be excused as happenstance, but if 2, then why not 3? If Vader didn't kill him successfully, how do we know Rei did? This is something a story can answer, but neither RoS or TLJ tried