@monaloren O.k. I think I get it now. Good thinking!
Still, I would suggest to give it a try (non-destructively!) to make the background completely the complementary color and then add a vignette (maybe not that strong..). See how that looks. If you don’t like it, just don’t use it, but at least give it a try…
It’s not Sunday yet, so still time to experiment;)
I’m sure you’ll get a great result.
Keep up the good work!