Or a good enough machine so that you never dip below native framerate.

That's tangential though. Whether or not you have skipped frames, G-Sync/FreeSync tend to reduce input lag, because the panel's refresh events will be timed such that they're closer, on average, to the times when new frames become available.

Even so you would never use vsync as it will introduce input lag in most gaming engines.

Most competitive players will have their own configs for competitive play etc. I have tournament/LAN configs, online play configs, and my video settings mostly stay the same. All tuned for lowest latency and highest visibility.