I've had a Samsung G40 25" 240Hz since April, but a few months ago I had an issue with Alt+Tab. When I do this, my monitor shuts down and loses signal. I have to unplug the power cable to get it back to normal. Therefore, I can't use Faceit, OBS, YouTube, or any other apps because Alt+Tab turns off my monitor. This only happens in CS2.
I use a 4:3 1280x960 resolution. I've updated all firmware and drivers, tested everything, and sent messages to Steam and Samsung support, but no one has an answer...
The only way is to use windowed mode, but the lag is very high and the game looks ugly.