In The Lord of the Rings: The Rings of Power, Elrond is tasked with saving the Elven race by gaining access to mithril, but there should have been far more accessible options to renew the fading Light of the Eldar. The Rings of Power introduced the idea that Khazad-dûm's mithril came from the light of the Silmarils, which was never part of Lord of the Rings canon. Even if the origin of mithril was the light of the Two Trees of Valinor, however, it would not have been the only source in Middle-earth.
https://screenrant.com/rings-of-power-elves-mithril-silly-light-reason/