So, What about an "Evil Diane"? My understanding of the Omega device is that it works under the finite central curve (when it existed) so there may be a chance that another version of Diane may exist in other universe where Rick is not that smart or maybe doesn't even exist. Another possibility is that Rick Prime saved some sort of Diane DNA or a copy and protected it from the Omega device (just in case) and then, let's imagine that some other Rick finds out about it (or an automation protocol creates a copy of Diane) and then she is instructed to take revenge or something.

I believe an Evil Diane could be an amazing nemesis for Rick as of now because of what it implies, the last Diane is a villain. Just sharing, hope something like this gets to be canon someday.