Aspiring to be a perfect support character? There's a manga about that called Is It Tough Being a Friend?
btw, don't even think about opening the comments to that manga. It's one of those where nothing but LN readers posting spoilers are present. smh
Seems like this series need something like this one 478758
💀💀💀(If this kind of comment not allowed tell me i will delete, kind of lazy reading law or a thing xD)
What she does is also somewhat close to the meaning of that word because she has “stolen” a few love-triggering events from the original story (though less than, say, Bakarina).