Lord of the Rings Series -- Amazon

rajncajn said
Pretty certain it's Saruman.

The problem with this is is totally against canon, as none of the Istari (wizards) arrive until 1000 years into the Third Age (which begans with the initial defeat of Sauron by Isildur / Elrond)

https://lotr.fandom.com/wiki/Wizards
But I wouldn't put it past the show runners to retcon this.

But that does further complicate why Gandalf didn't appreciate what the One Ring was almost immediately when he first suspected it when Bilbo transferred it to Frodo. Had he been around for the initial forging / gifting, War of the Last Alliance and capturing the ring, surely he wouldn't have had to travel to Minas Tirith to do some research at the Library of Congress to find out. He would have been able to figure it out immediately.

Taurus said
As they're both dead, official canon is set.
Just one item that's egregiously wrong is that Gil-Galad had no right to offer a trip West to anyone. The Valar themselves invited every elf everywhere (except a few whose actions/oaths precluded accepting) to come to Valinor and live there forever.

And it could be that at least some Elves took an oath to not return to Valinor until Gil-Galad granted them leave.