Repair or software modification of the Android phone screen?

Question

Android

Model Jiayu F1.
Problem: the bottom quarter of the screen, the touchscreen does not work correctly on it. Taps on the left side of this area are recognized as taps on the right side of this screen area. And on pressing the Menu button in the lower left corner of the phone there is no reaction at all.
Attempts:
1. I installed the official firmware successfully, but the problem remained.
2. Dismantled. I did not find anything unusual, the cables seem to be installed securely.
Question 1: How can this be fixed?
Question 2: how to programmatically change the Home and Menu buttons?
Question 3: or how to make the display 800x400 in size display a 600x400 picture, thereby covering the lower problem area 200x400, for example, in black?
ps Accordingly, I can’t enter the menu at the moment: the button does not work, and the icon on the display is in the dead zone.

Answer 1

Calibrating the touch screen with something, found here TouchScreenTune , but it may not work in it (not in the supported list).
ps as an option you can install a launcher in which you will remove everything from the bottom!