Chosen Solution
I replaced the display on my iPad Air 3 with the i fixit screen, but for some reason there is about an inch wide streak down the middle of the screen that touch doesn’t work on, yet it works everywhere else. Any thoughts on what could fix this?
Try reseating the connectors. If that doesn’t fix it then you have a defective screen or a damaged connector/ribbon cable. While you have it apart inspect the cables carefully and make sure the connectors aren’t bent. If everything looks good contact ifixit and get it replaced under warranty.