listen, is this a stretch? probably, but i'm like 75% sure they might parallel the byler kiss in season 5 to the famous notebook rain kiss and here's why.
last season, it was brought up that mike didn't write will any letters, and it clearly hurt will. despite this being a shocker (because why wouldn't you write your best friend???) it was never mentioned again. the topic of letters is so prominent this season that i'm certain this issue is gonna be brought up again next season. in fact, it has to be because we got no closure on it.
but how does this correlate to the notebook? i'll get to that. there's a popular theory that mike DID write to will, he just didn't have the courage to send any of the letters because his feelings were too transparent. this theory makes a ton of sense. there's also that track named letter to willy, which people correlate with billy, but they could've easily named it letter to billy c'mon now.
if this theory is true then a parallel to the notebook, one of the biggest pieces of romance literature and media, would make sense. in the notebook, noah wrote allie a letter every day they were apart, but she never received any of them, which is literally the byler letter theory.
in the notebook, allie brings up that he never wrote to her and they argue. noah admits that he wrote her a letter for every day of the year and then they share the famous rain kiss. the way that byler is going, it would make an astounding amount of sense for them to go this route and parallel the notebook. we know that the duffers love to parallel famous media, so why not parallel one of the biggest romance kisses in history? plus byler is already associated with rain and letters, it's literally the perfect scenario.
bonus: in the notebook, allie is a painter and noah is a writer. they're so byler coded.