Solved
How to change Game Resolution without opening game?
In a bit of a quagmire currently. Was at the 2nd boss of Blood Hunt Tactical and my FPS always drops. So, I decided to lower my resolution. No big deal right? I've done it before, just to compare...
When it goes like that on start up
Press ALT +Enter keys
There is also this guide (Link) to edit the client_settings file
