I'm going to be the outlier here and say most of the fics that try to pair Naruto with Kaguya feel like they're written from a place of pure power fantasy. It's rarely about character dynamics because, well, what dynamics? They've barely interacted. The draw is almost entirely about scaling those powers to ludicrous, universe-breaking levels.
Authors love to fuse the Tailed Beasts' chakra with the Otsutsuki god-tree nonsense, creating a 'chakra source' that's supposedly infinite. You get these long, tedious descriptions of Naruto's chakra turning white-gold or crystalline, and Kaguya learning to 'feel' emotions through his weirdly compassionate version of her power. It often reads like a DBZ fan trying to one-up the end of 'Shippuden'.
Honestly, the more interesting fics aren't romances at all; they're world-building exercises where Kaguya, sealed but conscious within him after the final battle, becomes a sarcastic internal mentor. That setup at least creates a dialogue where their powers—her ancient, detached godhood versus his modern, human-based ninjutsu—actually clash in a meaningful way, rather than just stacking multipliers.