I have tried and failed to use xrandr to set up my custom resolution of 1366x768 (it throws an error regarding the colour, it seems that there have been reports saying thai this is a problem inherent in Nvidia drivers, in my case 470 and later 510 with a GTX 1050 GPU installed in the machine). Is it possible to use the X Server GUI to set the resolution, if it is - how?
(Ubuntu 20.04)