game loads full screen,resolution is too small ,the settings button flashes in and out and unable to click on it -can get to battle page for example and play a battle but then can not get out of that window esc does nothing trying to click on X does nothing also trying to use a slider in a window does not work windows 10 ,steam verified files -etc
My husband was experiencing the same thing on his PC - the settings button was flashing in and out of existence and he couldn’t really play. Somehow he figured out the game was having an issue with a controller, namely his joystick. He disabled the joystick in device manager and was able to play after that. Unplugging it would probably also work.
No clue if that’s the issue for you, but just an idea 
Thank you !! un plugging my joystick from my computer solved the problem of the flashing /disappearing settings button-