That is interesting, I have found Peace Lilies to be more of a water hog here in my area especially when temps are getting hotter now.
My peace lily got fried in heat and lost all its leaves one time when my hubby thought it needs sun, not undestanding it needs shade and be kept moist. I was able to nurse it back, diligently giving it daily spritzing, keeping the media moist and in shade. Thankfully seasons were slowly transitioning and Fall was coming up then but temps still nicely warm.
In your 2nd to the last photo, it still has a potential to return nicely, I would put it back in a moist media, and put it in shade. Keep media moist, do not dry it out. Give it time to adjust and get back, it is a very resilient plant. You will need your patience and diligence to keep the media moist.
Have attached here a photo of mine, to show you how resilient it is:
