Glad you've found something that helps but it's strange that would effect input lag,
I've heard increasing brightness can increase response time. Can't vouch for it as I don't notice it on my 60Hz IPS but I do notice the difference from 60Hz to 72Hz when overclocked. For example in driving games the car/bike turns better whereas on 60Hz it can feel like it's understeering, oddly enough. I also get mild dizziness at 60Hz when I turn the cam sharply. And it helps with scrolling smoothness. So that's something Wyndmere could also try, to squeeze even more improvement out.