Everything else is a fanfiction. Even the Silmarillion. By far the most obnoxious reaction to the show is from "Tolkien purists" who got their entire Tolkien knowledge base from Peter Jackson.
The show is a perfectly Tolkienish story, despite the gratuitous lack of random singing, it's just not a good one. Like, okay, you need to compress the timeline for the show, fair enough, just do a good job of that.
Wrong Durins to fight both the War of the Rings and the Balrog?
Then don't tease the fucking Moria Balrog. If you want to use a Balrog, because Balrogs are fucking sweet, there was more than one...
Honestly, the weirdest part of the show is that they'll follow a lore deep cut with something that could only possibly fool someone that missed the deep cut, but also doesn't know or care who Gandalf or Isildur is, so what's the payoff for the reveal?