Amazon's will focus on the Second Age of Middle-earth's history, including establishing several legendary kingdoms of elves, men, and dwarves alike.
One such locale likely to be revealed in Amazon's The Lord of the Rings is Numenor, the island kingdom of men that forms the backbone of the Second Age's expansive narrative. Numenor will be essential to The Lord of the Rings' narrative as its story progresses, with the dark lord Sauron sent to corrupt the Numenorian populace in the year SA 1600. Numenor's eventual fall into darkness, and subsequent destruction, becomes the catalyst for the likes of Gondor to flourish within Middle Earth, including birthing the legends of several prominent characters in Elendil and Isildur ahead of the Third Age's inception.
In this way, Amazon's The Lord of the Rings can achieve the perfect, symmetrical handoff to where Jackson's The Fellowship of the Ring flashback began - with the alliance of Men and Elves fighting for Middle Earth's freedom on the slopes of Mount Doom. Elendil, in particular, establishes Gondor, forms the first alliance of Men and Elves, and leads The Faithful after the fall of Numenor, which banished Sauron to Mordor. The king then begins Gondor's 1000 year war against Mordor, with Elendil subsequently leading the free peoples' coalition into Mordor to destroy Sauron - closing the loop to Jackson's original trilogy.
It is likely not a mistake but rather by design that ' Second Age setting allows the inclusion of both Elendil and Isildur towards the end of the age cycle, as well as their great kingdom of Numenor at the peak of its powers before it is destroyed. Numenor's fall happens during an event known as The Changing of the World, in which the great city is sunk by tidal waves that quite literally change the topography of Middle Earth (turning it round). This event not only robs Sauron of his original, beautiful form but also forces the good-aligned men out of Numenor ahead of its destruction, with the leader of The Faithful Elendil subsequently forming the kingdom of Gondor.
Elendil and his son Isildur then engage in a thousand-year war against Mordor (which sits opposite Gondor) that ends with the pair leading the free peoples against Sauron's forces on the slopes of Mount Doom. This epic event is where The Hobbit movies, with the new trilogy feeling off in of both narrative stakes and tone compared with the original films. The best ending for Amazon's The Lord of the Rings, therefore, is to make a climactic connection to the opening scene that began Jackson's seminal trilogy back in 2001.