Actually that's the thing, this is a weird type of genre that is suppossedly based on an "original premise" where what you described happens, but actually, there is no such thing. These pre-stories are made up, there are no otome games with "villainess" and shit like this, these were all just made up by the original villainess stories that became popular on syosetsu, a japanese page for web novels. So unfortunately you won't be able to find the original source, because there isn't, its a cliche made surrounding a cliche that doesnt exist. I am sure there are some stories now that do the original premise somehow, like going full circle from being something made up to something that is now being made as "original" compare dto the usual mc being self inserted as the villainess instead and doing good things instead of being evil.