Extreme latency in menu/game - Latency Reduction option cannot be enabled even if not grey'd out.

[jaunty spear]

need help with something in the settings, so basically my mouse cursor in the menu and the whole game pretty much feels a little bit delayed/ with latency, and so i tried enabling the latency reduction option in the menu but it physically doesn't let me enable it even if its NOT grayed out. any help please? its kind of ruining my experience. when i first played it fully when it came out it wasn't like this idk what went wrong