Horse Stall Window

The goal today was to intentionally underexpose shots by up to five stops ISO, and then recover the final product.  The event was something called the 'Fun Event' at a farm near by.  The equestrian event was an interesting way to spend a Sunday.
But first the disclaimer.  My learning curve got ahead of my goals for the day.  One of the YouTube videos I was watching explained the benefits of the camera program Banks.  Good enough for me.  I created three banks.  One for standard settings, one for HDR setting and one for low light.  Guess what I chose today?  Yep, one of the new ones not for HDR.  When new banks are created or are used, the default settings are used.  Shooting in RAW is not a default.  Guess what happened?  Yep.  JPGs only.  On the bright side, it was JPG Fine in a large format.  Not a total disaster.  And, in a good way I'll get to see how much software has improved over the years to handle JPGs.
The goal today was to shoot action shots in crappy lighting.  Action being defined as 1/320 to 1/500 depending on the amount of movement.  And intentionally under-exposing the shots by lowering the ISO.
One of the downfalls of using this methodology is the preview images are all very dark.  So it may be a while before I get through all of them.  Maybe I will put them on the laptop and take them with me next week?  Post from the road.
If the rest of the JPGs turn out as well as my first effort, I'll be very happy.
I'm guessing there were about 20 to 30 families at this equestrian event today.  In each class there was probably an average of five riders.  There were judges and there was a support group.  And there were ribbons given out.  Very cool.
And everyone let the one that didn't belong (me) roam around.  Very nice people.
I moved around a lot.  During the moving about I passed a stall with the occupant looking toward a very dirty window.  It was a clean dirt.   It was barn dirt.  Maybe overly dusty?  So the stall is very dark and this light is hitting the occupant very nicely.
Yea, this isn't my normal interest.  But the scene did whisper to me.  Didn't talk, just a whisper.  And that was enough.  The question is, shooting in JPG, can I save it?

Horse Stall Window

NIKON D500 Ver.1.20/18.0-200.0 mm f/3.5-5.6

20 mm, 1.125 sec, f/5.6, ISO 800

EV +2, MANUAL Mode, Size DX

I get it, it's dark.  I ran a version with a bit more light, but the stall walls sort of took away from the horse.  The light on the horse is what gets to me.  Just enough to see the horse's face, or part of it anyway.  I don't generally favor dark images, but again this one whispers to me.
This may be a candidate for a paint job, in which case I would lighten it up considerably.
On a related note, one of the Topaz modules is a JPG to RAW program.  Since I have a number of JPGs to work with, maybe I should try it.  30 Day free trial.  Yea, that's the ticket.  That's why I shot JPGs only.  HA.