Input lag on steam?

I've had this problem for a while now, and honestly it's really annoying as it limits the difficulty of the levels I can beat. I've gotten a new pc (obviously not just for gd lol), tried using different input methods (mouse, keyboard, controller), and also tried using different monitors, but none of them have permanently helped. The only way I can get rid of input lag for sure is by playing in fullscreen mode with vsync off, but it's just too overwhelming on my eyes and the screen tearing is unbearable. Does anyone have any fixes? would be greatly appreciated as I've been trying to solve for quite a while now