Hi, I just bought Asus RTX 2060 turbo as well for my son`s G20AJ, it works fine, unless the keyboard & mouse is not detected on boot, so i cant enter to bios setting, but will be working again after entering windows. I m still working out to find the fix.
Note: You can`t put RTX founder edition in G20AJ, no airflow outake can cause overheat. You have to get a blower type of fan like Asus RTX 2060 Turbo.