Hey there!
Since this isnโt something we tested on this TV, I canโt say for sure what kind of impact it has. Generally speaking though, since input lag adds processing, we do expect it to have at least some impact on input lag. However, it shouldnโt add a very noticeable amount of lag. So, if it isnโt something youโre particularly sensitive to, then you can probably get away with enabling local dimming without any issues. Worst case scenario, if it bothers you, simply turn it back off!