"After Morgoth's defeat, the one you call Sauron devoted himself to healing Middle-earth, bringing its ruined lands together in perfect order. He sought to craft a power not of the flesh . . . but over flesh. A power of the Unseen World."
--Adar, The Lord of the Rings: The Rings of Power (season one, episode six)
There is not yet a One Ring, that renowned physical object which channels spiritual power and represent its allure, in Rings of Power. Set in a prior chapter of Middle-earth's history, the show introduces not only new backstory to the screen, but also a more egalitarian set of societies than any in Peter Jackson's Lord of the Rings, greater romantic tension, and more layered thematic complexity. Core aspects of the original films still shine through, such as the strong emphasis on deep friendship. Indeed, friendship is one of the most prominent themes here--same gender, opposite gender, and cross-species friendships are persistent from start to finish. Nori and Poppy, Galadriel and Halbrand, Elrond and Durin IV, and Isildur and his two companions very nicely complement the friendships of Sam and Frodo and Legolas and Gimli in the main trilogy of films. In some of these friendships, though, there is still a degree of nuance and inner moral conflict not present in most other depictions of Tolkien's world. Galadriel and villains Adar and Sauron (more will be said about them near the end) exemplify this.
That is not to say that every villain mentioned or shown is in more sympathetic light. Morgoth, who defied Eru Iluvatar (God), is presented as if he only twisted what had already been created for his own evil purposes, a kind of popular satanic archetype like David in Alien: Covenant. Both of these characters from very different settings are desperate to seize the power of creation for themselves after finding they are not at the metaphysical level of their respective creators. In spite of how theological concepts of Tolkien's universe are being addressed here, there is no Biblical statement that Satan cannot create of his own power. All contingent beings and objects would cease to exist if the uncaused cause itself ceased to exist or simply revoked its will to metaphysically sustain its creations, as well as that which its creations have produced, but there never is any sort of doctrine entailing that Satan or other demonic figures cannot actually create anything. This is but one of many ways that mere assumptions based on idiotic traditions have shaped culturally widespread but erroneous ideas about the Christian devil.
There are still ways that Rings of Power and Lord of the Rings in general are more consistent with the Christian philosophy they are ultimately rooted in. At the end of episode seven, the Balrog under Moria that is later defeated by Gandalf stirs. When Gandalf calls the Balrog a "demon of the ancient world" in The Fellowship of the Ring, the genuine Christian meaning of that word is in reference, for the Balrogs are fallen Maiar, or Iluvatar's angelic beings that rebelled with Melkor--the same being who became Morgoth. Melkor himself was a Valar, a higher angel than the Maiar, and thus his revolt against Iluvatar somewhat parallels the ambiguous rebellion of Ezekiel 28's unnamed, wicked cherubim (though Genesis neither addresses the history of fallen angels as The Silmarillion does nor mentions God using song in creation). The Biblical Satan Melkor is meant to reflect is not necessarily unable to create of its own accord as can Yahweh or Eru Iluvatar, called "The One" in the show, but some Maiar mirror fallen angels more closely.
However, there are hints in Rings of Power of how even the corrupted minds and bodies of those who have defied Iluvatar are still in part reflections of The One's goodness and creative capacity. This, too, parallels Christian philosophy, in which the initial state of created things, physical and nonphysical, was "very good" (Genesis 1:31). Protagonists like Galadriel are also not treated like paragons of unflinching righteousness, seeing within themselves some of the same desires, tendencies, and ideological leanings behind the actions of those they would condemn. Galadriel even finds that the central villains of the show do not actually show an interest in sheer malice or selfishness, and it is they who speak to her of the goodness of The One. They speak of him with regret for the state of the world. There are appropriately serpentine, conflicted motives that come to light within Adar and Sauron, beings who speak of The One without ever denying the existence of this entity without whom there would be neither world nor created creatures. Adar, the "Father" of orcs, even says he turned against Sauron when the latter used too many of his orcs for his own ends, fights for the orcs to have a home where the sun's light does not afflict them, and shows a pained expression and watery eyes when he kills a wounded orc in what is appears to be a mercy killing.
When captured, Adar directly tells Galadriel that her quest to vanquish evil should lead her to her own reflection in a mirror: her aggression has not always been channeled in ways that would be just, at least not by the Biblical standards that Tolkien, as a Catholic, would not have fully understood (Christianity is an inherently theonomist religion that contradicts the legalism of Catholic ethics). Adar insists in that same conversation, speaking of himself and his orc children, that "We are creations of The One" as are other beings, appealing to the sacredness of conscious beings descended from God, however voluntarily marred by evil they might become. Even Sauron claims in the season finale of Rings of Power that he wishes only to heal the world by presiding over it as he recalls the light of The One, so that he might be forgiven for aligning with Morgoth. There is talk of repairing what is morally flawed in the world, and though the One Ring has not yet been crafted and there is plenty of time for Sauron to descend into unbridled arrogance and malice, his first steps towards prompting the creation of the Ring do not reek of intentional tyranny. In the show's Sauron, the contrast between innocent and egoistic intentions behind power is given more attention than much of the films allowed.
These are far more morally mixed versions of Sauron and Galadriel than one finds in Peter Jackson's excellent trilogy of films, not that they could not lead up to them becoming the characters seen later on. While never portraying anywhere near the extremes of stupidity and depravity regularly shown in Game of Thrones, the heightened complexity of characters who could otherwise appear to be static archetypes (which is not intrinsically a negative thing when handled right) makes Rings of Power the ideal Tolkien-based show for audiences who, even if they never rationalistically contemplate things either on their own or with prompting, have seen the elaborate war within the human heart in the tale of Westeros. There does not need to be a One Ring or an Iron Throne for someone to seek power for arbitrary, hypocritical, or otherwise irrational ends, but not everyone who is irrational or unjust has wholly given themselves over to these qualities. Assumptions, contradictory beliefs, and emotionalism are all that a person needs to believe whatever they think justifies their worldview and actions.