I can't access the final stage in Shadow Generations

[Bargoth]

I beat Mephiles, got the cutscene with Black Doom, followed the next quest marker to the final stage pillar, now I need to get into the final stage to confront Doom, but I'm stuck. I'm on the pillar leading to the final stage, but I get a message saying "Some Black Moon Eyes are still closed. Doom's Eye in the Doom Zone needs to be taken care of first."

It then set my quest marker back to Sunset Heights, even though I had already completed both acts of Sunset Heights, now twice because it keeps sending me back to it. Doesn't matter how many times I complete it, it keeps setting my quest marker to Sunset Heights.

What do I do?

[Relic]

If you didn't attack Doom's eye in act 1, you gotta do that real quick before proceeding to the final levels/boss. I hope I helped!

[Shade Vortex]

This isn't explained well at all by the game but you have to attack Doom's Eye at the very end of Sunset Heights. You get an attack prompt right at the very end of the last section (where you normally ignore him and go past him to the goal ring). It's pretty tight timing-wise since you can't hit him after you pass him, and you only get one shot at it- there's no way to die and just re-attempt that section. Honestly annoyed me...

[Stormeko]

I had the same problem! You're suppose to hit Doom's Eye at the end to get the shadow piece thingy (Idk what the official name is) That'll open up the last eye on the black moon and let you continue!