the elessar

[Galin]

Appendix B notes:

The Third Age

These were the fading years of the Eldar. For long they were at peace, wielding the Three Rings while Sauron slept and the One was lost; but they attempted nothing new (...) [something about Dwarves... something about Nmenoreans] (...)

... and next we learn that around 1,000 years [a notable amount of time] 'had passed' and the arrival of the Istari is described. And in step with this: 'Yet after the fall of Sauron their power was ever at work...' Of The Rings Of Power And The Third Age

Come on now Tolkien doesn't have to spell it out explicitly with respect to Nerwen.

The Elves had, in my opinion, already wielded the Three in the Second Age, and even Christopher Tolkien rather simply notes that Galadriel would have to await the fall of Sorehead, in a comment about the possibility of her using Nenya after the Ring Ruse was discovered.

Although subjective of course, I think the possibility you raise about Galadriel is more strained than Olorin visting Middle-earth. Again everyone seems to accept Melian for instance, or some of the Valar.