Linton is an important location in the Rings of Power, where many elves gather during the Second Age. This key location is hardly mentioned in Frodo's adventure "The Lord of the Rings".
In Tolkien's book,. The elves had already weakened in the Second Age, and Linton's fall was linked to the devastating tragedy of the Second Age.
Linton still existed in the Third Age, but it was not as powerful as the Second Age, and its population was greatly reduced.
The most obvious reason for such a dramatic change in Linton's importance is that Gilgalad died at the hands of Sauron and the elves lost the High King. Serdan took over Linton after the Battle of the Last Alliance, but the number of elves killed in the battle with Sauron reduced the population of the Kingdom of Linton.
further weakened their population and influence in Middle-earth.
Of course, as The Lord of the Rings shows, many elves are also left behind, including Elrond and Galadriel. But they settled in two other strongholds, as Linton was partially destroyed after the war and the fall of Númenor. However, it was in better shape than Celebrim's Eregian, who was wiped out by Sauron's army.
In light of the destruction of Eregian in the Second Age and the decline of Linton, Rivendell and Lotslorien effectively replaced them in the Third Age.
That's why these elven settlements appear in The Lord of the Rings and not in the kingdoms of the Rings of Power.
The elves who previously lived in Linton and Eregian migrated to these places, including Elrond and Galadriel. Linton is still there, but it's barely visible on Frodo's journey.