This past Friday we were finally able to see ‘Aliados’, the eighth and final episode of the first installment of ‘The Lord of the Rings: The Rings of Power’. With the filming of the second season already underway and the idea that it will end up consisting of five, the showrunners JD Payne and Patrick McKay have given some clues about what their future plans are for the Amazon Prime Video series.
It is true that they had already commented that the second season was going to work a bit like ‘The Dark Knight’ with Sauron taking as a reference characters as mythical as Walter White or Tony Soprano, but Payne and McKay already think in the very long term. For this reason, in his participation in the official podcast of the series, McKay has highlighted the following:
There is a long-term plan, with great moments along the way and a very specific and clear end point. And this applies not only to the big narrative plots, but also to the character arcs. But you have to leave enough leeway along the way for discovery and surprise, and to take advantage of the unexpected things that are discovered along the way. Like, you know, actors who have great chemistry or an actor who has great acting range that you didn’t know about. And so, oh well, wait a minute, how do we mix that in here and take advantage of it? And again, just looking for opportunities for delight always within a general path that has clear markers along the way.
Come on, that ‘The Lord of the Rings: The Rings of Power’ has a fairly clear point of arrival, but that is not going to prevent them from making the adjustments they deem appropriate to reach it. In this regard, there some statements by Payne during the last Comic-Con clarify much more what can you mean by that the series has a very specific ending:

It is the rise and fall of Sauron. That story seemed to us that it could live up to the greatness that we can give it.
The first season has served to reveal the identity of Sauron and the initial steps of his plan to forge the One Ring. Everything points to the fact that he will now continue to grow until he tyrannizes Middle-earth and that the fifth season will most likely end when he is defeated in the War of the Last Alliance that we could already see briefly in the prologue of ‘The fellowship of the ring’.