> raising of a huge army is indeed one of the goals of the protagonists
It's not. They always acknowledge that their army will be much too small to defeat Sauron's in a war. They luckily win a battle outside Gondor. They defeat Sauruman only with a deus ex machina moment of supernatural aid. But when they march on Mordor they send only a token force; they know they can't win that way. They can only slow down and distract Sauron.
The way they win is trust in innocence, a thing and a plan that Sauron can't even envision - that's explicitly Gandalf's thinking. Sauron never imagines that a couple of essentially civilian hobbits, the least powerful people, would be given the Ring, and that they'd enter Morder on their own, that they'd have the courage, and that the good guys would actually destroy something of that much power when they could use it.
> it only takes a small shift of perspective to see how the LoTR will appeal broadly to anyone who believes in good vs evil narratives
I agree in a way: People who don't read the book with a little thought can just read a superficial action adventure, good guys fight bad and win. And Peter Jackson's films are 90% the latter.