My Screen Doesn't Have The Right Resolution With OpenGL

[SomeDoge]

So, I bought 5 inch GeeekPi LCD Resistive Touchscreen Monitor. When I tried to enable OpenGL with it after rebooting I could only see only top-left part of the screen, the rest is "there", but out of screen borders. PLEASE HELP! When I try to plug it into TV screen everything seems to work fine.

[Imperf3kt]

Does it exhibit the same behaviour with the OpenGL driver disabled or using the other mode?
I have a couple of 5 inch screens that I must use fake KMS for. If I use full KMS, the screen duplicates itself vertically, is patchy and full of white noise. It looks similar to an out of tune UHF TV.