PixInsight did a pretty decent job at "fixing it", considering I had a tiny lossy JPEG to work with
Lots more hiding in that data as you can see!
I ran:
SCNR to remove the green, followed by BackgroundNeutralization to remove residual blue (though the stars remain a touch cyan), then a ScreenStretch loaded into HistogramTransformation to stretch it while maintaining the structure fairly well. Blew out the core a little, but you need to tweak the main files NOT to (a single JPEG is NOT the place to maintain structure well
)
You CAN do the same in PS, but never really looks as good because of how PS handles the dynamic range IMHO.