A Xanatos Gambit is a situation where every possible outcome has been engineered to suit you.
For example, let's say I'm the evil queen of Dublin (it could happen. . .). I want to conquer Meath and Kildare. I subtly trigger a war between the two of them. If Kildare wins, I can take over the weak and vulnerable Meath more easily than Kildare can, because I'm bigger. The same applies if Meath wins. Either way, I get closer to my goal. And once I've got one of them on-side, it's much easier to conquer the last one.
(In real life, Cork would notice this and refuse to stand for it. But since I am not the evil queen of Dublin, we can assume this whole premise is fictional).
Anyway, my own Xanatos Gambit regarding being published was always this:
I'll work really hard and keep trying and I'll never give up, which will maximise my chance of getting published. And if I don't, I'll leave instructions in my will that my heirs are to keep trying so if I don't make it while I'm alive, I can hope for posthumous publication.
Yeah. I don't handle uncertainty well.
Now, though, writers have a new Xanatos Gambit:
I'll try to get published. If that doesn't work, I'll release my work as an ebook and become the new JA Konrath. And if I don't become the new JA Konrath, the man makes a darned good point that there's no limit on time or shelf-space on the internet, so maybe I'll be a bestseller in ten or twenty years - or even after I die!
Remember, with Xanatos thinking, you're the winner - no matter what!