Hello! I had the same problem that you are facing. My touchscreen was failing exactly on the same spots. I replaced the digitizer and the problem persists. After weeks of research I found a thread on the gbatemp forum that a person was having problems with the touch and he decided to recalibrate the touch through a custom bootloader (Hekate). In the tools tab in the lower right corner there is a tool to calibrate the touchscreen. I clicked on it and magically after the process my touch is 100% functional. Unfortunately, this fix is only for consoles that have access to the custom Hekate bootloader (which on newer consoles are blocked by nintendo). I hope this information helps people who are facing this problem.