iPad Air 4 screen becomes incredibly dark after jostling

I'm having a persistent problem with my iPad Air 4. Whenever it gets jostled around (e.g. tossed on bed, falling from short heights) the screen almost stops working. It still turns on and the screen DOES WORK, but it's incredibly dark and requires a bright light held DIRECTLY to the screen in order to see and select options. However, I can restore it and it makes sounds when I connect it to power. The first time this happened, I repeatedly restarted it, restored it, left it on the charger for multiple hours, used different cables & ports, and eventually took it to the Apple Store. They were not able to help and I had given up, until it randomly returned to normal after a period of time.

It's happening again and I have done all the steps I listed above, but I will leave it alone for a few hours to see if there's any change. I would just like to know if anyone may have an idea as to what is wrong. The Apple Store wasn't able to tell me anything except that my iPad was no longer working and that I could recycle it. A third party was the one that told me my iPad was in almost perfect working order EXCEPT for the exceptionally dark screen, but misidentified it as some sort of screen damage that would require a screen replacement.