So like, when she gets resurrected, how will the people who knew her be affected? Aki has spent the last 5 years mourning, so when Koharu comes back looking like she hasn't aged a day, how is Aki going to mentally process that? Like, you can't just easily paper over that with memory manipulation. Even if you make her forget about Koharu's death, she's still going to be 6 years younger than Aki by the time she's alive again. Aki, who knows her primarily from being classmates in school. How is that gonna be rationalized? What about Koharu's parents? They had to bury their teenage daughter half a decade ago, but then she'll be back one day looking as if nothing happened? Mourning isn't something people just do privately, it affects major life decisions. So if you retroactively undo Koharu's death, all her loved one's actions since then won't make a whole lot of sense, even if you erase their memory of her dying. Without her death as context their remaining memories will still be nonsensical.
All this kinda makes me suspect that being resurrected is an empty promise that no cupid ever achieves.