So, there is only one way for the end to make sense: Sauron somehow corrupted the three Elven Rings. Galadriel not only is the sole responsible for the return of Sauron (!!) but she is also now devoured by a "righteous darkness" which will only expand once she gets a Ring. There is literally no coming back from this except via a final sacrifice and death (which is impossible, unless Amazon somehow has the rights to kill Galadriel): it is a very bad retelling of the story of Palpatine and Anakin Skywalker. Given these assumptions, it is easy to see why Sauron just went away: the elves and now firmly under his grasp. Under the premises of the show, if Galadriel had halted making the rings, then the elves would all have to leave Middle Earth to return to Valinor. Yes, that is nowhere in Tolkien, but it's what they've chosen. Galadriel doesn't want to leave, because she wants to kill Sauron. So I think her intent is to use the weapon of the enemy against him. This, however, is the very reason why Sauron should simply have killed Galadriel and destroyed any means for the elves to forge the Rings. As I said, the only reason for Sauron to allow the forge of the Elven Rings is that he, somehow, will control them.
And, as I said, this will not happen. What I just wrote, literally, never entered the mind of the scriptwriters.
Yes, she is sliding into darkness - but I suspect it is walking into a trap because she thinks that getting through the trap is the only way to beat the enemy. I don't see much parallel to the Anakin Skywalker storyline, because Galadriel has been intent on killing Sauron from the start. I suspect there may be parallels to the Doctor Yueh storyline in Dune - someone who hates their enemy so much they are willing to betray their allies for a chance to kill him. In line of principle I agree with you. However, both Anakin and Galadriel are actually manipulated by the local Evil Baddie(tm) and believe in a Greater Good(R) reachable only after "touching darkness" (an open fixation for Galadriel). Sauron even explains to Galadriel why she is
the sole responsible for his return (in a scene worth of Ellery Queen).
I think the writers still plan to keep consistency with the Lord of the Rings films (though obviously not the books). Amazon Studios is contractually obliged to prove that this show will never reach the LotR films. They, literally, have to
prove that RoP and the films are not happening in the same universe. This led originally to the death of Celeborn - now corrected in a pickup shot where Galadriel says that he is MIA (Why she isn't looking for her husband? Dunno, I guess not even they do).
So, maybe Elendil and Gil-galad will survive, or it will be Galadriel who will cut Sauron's finger (with Isildur picking up the One Ring). Anyway, they must do something big and clear that will break any continuity with the films.
So Galadriel will eventually be redeemed, Isildur will cut off Sauron's fingers, Elrond will unsuccessfully take him to Mount Doom, etc. But a bunch of unexpected stuff may happen along the way and most of the characters have an unknown future. The problem that I see is that Galadriel is beyond redemption - except via the classic "act of redemption ---> death". I don't think that these guy are realising the place they are in. The result will be an aberration.
Anyway...
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