Try adding this FX chain and see if it works for you. Good luck!
Put 3 filters, a “Invert” (at 100%), “Color Corrector”, “Invert” (at 100%).
Then, lift up the gamma of the color corrector in the middle.
This darkens highlights first, in the logarithmic fashion, more like a “iris closing” way.
You can also put a color corrector secondary to select reds and lower the gamma a bit.