I tried raspi-config but is has very limited options to choose. And even those don't take any affect after reboot. For example, the appearence of the screen stays exactly the same after changing resolution.
I have a 7" touchscreen attached to my Pi 3b+, and the right side of the screen is off ( about 50 pixels missing I guess ). I cannot enter any overscan values in raspi-config, it only enables overscan... Looks like I am pretty stuck with this.
Where is the config file where raspi-config is writing to, and can I edit there more options like screen rotation, overscan value ?