oooh ive never heard that song before, but i think i might have some fics you might like? (hopefully they fit what you're looking for, or i hope someone will reply on twitter with their own recs!!)

• the gauze of flowers (a love poem) by inconstantmoon

— its a rlly soft, kind of hurt/comfort hanahaki disease, where both hj and sh are pining for each other but dont realise it

• sleep paralysis by idrilka
— the ultimate pining fic, honestly for the angsty "i love you so much it hurts" mtz fics, i recommend anything by this author

• after the tone by tremulousbird
— this one made me cry, idk how well this fits the song you mentioned, but you can certainly feel sh's heart breaking while reading it

• undertones of sadness (loving leads to bleeding) by pinkhwxtiny
— its part of a series but i dont think you need to read the ones before this to understand it, this ones leans heavy into the quiet love/comfort type since neither are willing to rlly speak their feelings out loud (be aware that its a fic meant to connect to the next one so the ending is a bit open)

• you wrote for me (your words on my skin)
— soulmates au where both sh and hj spend most of the fic thinkings their feelings for ea are not reciprocated (if i remember it correctly) genuinely such an amazing fic

i hope these fit what you're looking for!! (ill leave all the links in a twitter post!)