The device you linked shouldn’t add any input lag. This device is passive, meaning that it doesn’t do anything to the signal (upscaling for instance). Passive devices are often easy to spot because most of them don’t require a power source like a USB cable or a power supply. Some devices use power that runs through the cable though (like the “Pound HD Link Cable v1” for OG Xbox for instance), so keep that in mind. Basically, something that doesn’t have a micro-controller will not add any lag (OSSC adds 0.2ms if I’m correct, which in this case is absolutely nothing)
With that type of devices, the worst that can happen is deteriorating the video quality, just avoid to daisy chain too many of them. Bob from RetroRGB got an issue with a passive “DVI-D to HDMI dongle” similar to the one you linked, he was surprised this could have such a noticeable negative effect (I’m was surprised too, that’s a good lesson I think). So, bear that in mind too, even though it’s not common, you should always consider that these devices CAN cause issues too when you try to diagnose a problem.