It will absolutely add some latency compared to the original controller but whether it's perceptible to you or any other human being is another matter entirely. I find 8bitdo sometimes have terrible lag in some of their devices, but it could be down to shoddy firmware and sometimes get patched later, like with the SN30 Pro for Android which was unusable before firmware patches.

I'm personally just semi-sensitive to lag, but for serious gaming I will always go wired for the psychological edge. I will get this regardless because wireless controllers are amazing for casual gaming.

I'm actually more interested in how much lag the USB-C passthrough introduces. If that can be down in the sub-3ms range, that would be amazing.