Consider looking at this forum.arduino.cc/t/using-millis-for-timing-a-beginners-guide‌​/… What you need to do is create a timer that every 60 seconds executes the code that you want and sets a flag if it was successful and based on that you can do whatever you need with the GSM.

try connecting the GPIO pin to the supply voltage of the ESP32 (3.3V) through a resistor and see if it becomes the maximum value. Maybe there is some flux left on the pin or something that affects it's response to voltage.

Considering you already can put a pixel at any position of the display you can try and use something like described here: softwareandfinance.com/Turbo_C/DrawCircle.html

Did you hold the Shift button while clicking upload?