I wholeheartedly agree. I'm glad that Amazon wanted to be ambitious, but there's so much great fiction out there that hasn't yet been adapted, even of other Tolkien stuff such as the Silmarillion (not exactly a story but still plenty of rich details about the world).
I will say, it at least goes down smooth as turn-your-brain-off entertainment if you are looking for something that just looks nice. A lower bar to clear, but I liked having something to fall back to when I ran out of House of the Dragon.