If you really want to minimize latency on a modern system, and can choose whatever commodity hardware you want, you can get the input+rendering+scanout delay below 10ms. At that point it's a matter of how often your screen accepts new frames. And with a high-end, frame wait plus pixel response time can also be under 10ms.

20ms for local end-to-end latency is a completely achievable goal.

https://www.blurbusters.com/gsync/gsync101-input-lag-tests-a...

Their best combo here achieved an end-to-end latency of 12-15ms, on a 200/240Hz screen with counterstrike running at 2000+ fps.

At a more mainstream 144Hz to the screen, running the game at 'only' 288Hz, end-to-end latency was 13-19ms.

Even at 60Hz they could easily keep the latency below 30ms.

As for touch screen technology, the Apple Pro Pen I believe is only 20ms and is state of the art. While I do believe that developer ux has contributed to lazy resource management, it's also clear that sub-60hz latency has regularly required exotic hardware.

Touch is hard to keep ultra fast. But with physical buttons it's mostly apathy.