I don’t think you can correct that very well afterwards. At least not without a lot of effort.
For situations like this, polarization filter is your best friend. 
However, scene has tempted me to test some GMI’C filters.
First I tried to neutralize the reflection to some extent in darktable:
2022-01-25_12-58-48.53_DSC6109.NEF.xmp (14,6 KB)
And then in GIMP - after some dodging and burning - I used GMI’C filter inpaint (multi scale) to smooth the separation in the middle and at the end colour grading filter to change the colours and contrasts a bit:
It could certainly have been done better with more effort, but it is enough as a demonstration of what can be achieved with free software. 