I didn't see if you've posted the metadata with ISO and shutter speed. I'm thinking there is still more in that camera in terms of bumping the ISO for better exposure. Of course you will instroduce more noise as the ISO increases, but is something that can partially be handled in post with the right software.
I downloaded your image to see what detail might be there already. You might be able to see the huge amount of noise, while there is more image. I suspect that if you can increase the ISO you'll have some noise, but not as much as trying to increase the brightness of an underexposed image. But I think there is more there. Can you provide metadata?
View attachment 117976
View attachment 117977