The idea that the Three Rings of the Elves are uniquely suited to protect, heal, and restore is found ad-nauseam in Tolkien’s writings. “The Silmarillion” explains that, when it came to the Three Rings of the Elves, “of all the Elven-rings Sauron most desired to possess them, for those who had them in their keeping could ward off the decays of time and postpone the weariness of the world.”
In a letter Tolkien wrote in 1954, he went into even more detail, explaining that of the Elves, “Those who lingered were those who were enamoured of Middle-earth and yet desired the unchanging beauty of the Land of the Valar. Hence the making of the Rings; for the Three Rings were precisely endowed with the power of preservation, not of birth.” In another letter written in Tolkien wrote to his publisher in 1951, the author explained the concept again, saying, “The chief power (of all the rings alike) was the prevention or slowing of decay (i.e. ‘change’ viewed as a regrettable thing), the preservation of what id desired or loved, or its semblance — this is more or less an Elvish motive.”
See the connection there? The Three Rings are ultimately made to preserve what the Elves already had — which is precisely what they’re trying to do with mithril in Season 1 of “The Rings of Power.” So, while the whole “mithril is imbued with the light of the Two Trees via a lightning-struck Silmaril” storyline doesn’t have a direct connection to the source material, it looks an awful lot like the writers are setting the stage for the Elves to try making some powerful rings, you know, if the whole mithril thing is a nonstarter.