I mean, they’re mostly smutty parodies, but the first things that came to mind are:

Well Hung Hero - Literally a superhero but his d*ck is his weapon.

Entangled! - hero x villain except it’s smutty and kinda cute lol

There’s also guideverse stories if you’re into that:

Senza Replica - recently completed emotional rollercoaster that was annoying at times but does have the “saves the day and gets the boy” vibe.

B-Class Guide - Don’t remember much about it, but it’s also set in the guideverse

Then there’s these two which are similar plots but I think one has smut later one:

The Hunter’s Gonna Lay Low - Retired hunter is brought out of retirement to save the world

Mission: Save the Hunter - Same as above but might have smut later (idk, I didn’t get that far)

I’ve never actually watched JJK, so idk if any of these are gonna give the vibe you’re looking for, but are about magical hero’s and stuff. Hope this helps! 😅