Spending time in the 'Yamada x Miyamura' tag feels like watching two plants grow towards the same light, roots tangled under the soil. Most fics get Miyamura right from the jump—they lean into his transformation being less about the piercings coming off and more about him learning to accept care, to stop being just a passive observer of his own life. I read one recently where he quietly starts a garden on his balcony, a small act of nurturing that Yamada notices but doesn't comment on, and that sort of subtle shift gets me every time. The external markers change, but the internal permission to want things, to take up space, that's the real character arc.
Yamada's growth is messier and way more fun to write, I think. Canon gives us a girl obsessed with image, so fanfiction loves to dismantle that brick by brick. It's not just about her becoming 'nicer'; it's watching her vocabulary of care expand beyond food. She learns to sit in silence with him, to offer the weird, specific comfort of just knowing what he needs without the performance. The best stories show her realizing that being seen by him, truly seen, doesn't diminish her—it actually gives her a sturdier kind of confidence.