touchscreen stopped working completely

the digitizer for my iPhone 12 pro max simply stopped working completely one day. I believe it was from the leather case that I purchased from Apple that might have had something to do with it. Summers in the high dessert of SoCal get intensely hot so I would remove it every time i had my phone on to prevent it from overheating, over time I started noticing an air socket on the top part of the screen close to the front speaker every time i pressed on it. I had read comments about how some cases will mess with the adhesive keeping the digitizer and the LCD screen intact resulting in the touchscreen malfunctioning. So what I want to know is if there’s a way for myself to find out if I can’t still fix the digitizer or is my only option to pay for a replacement which at the moment isn’t going to happen since I’m unemployed. Also i had factory reset the iPhone and since the touchscreen isn’t working, I can’t even turn it off I have to let the battery die to turn it off, I can’t even connect the iPhone to WiFi or Bluetooth. Please someone help me with simply figuring out if there’s anything I can do to use my iPhone again at least to control it with my other iPhone which I’m using rn through control nearby device or something