Need help finding a BL

Super cute n fluffy. I dont remember if there was any smut, but there WAS a kiss scene while main couple were working together on a banner after school. All I remember from this BL is that the Uke believes in luck and karma and allat (excuse my lack of vocabulary) despite his appearance being intimidating (?). He idolizes a woman who is like an etsy witch (or wtv he’s into) and collects her merch, which is in the form of keychains. At the end of the story, once the couple get together, its revealed that Ukes idol was his current boyfriends sister all along.

Clearly, I’ve got vague memory of this story, but it was short n sweet n something i read a long time ago＾ν＾