Where are you measuring the keypress from? The nerve signal to your finger muscles?> Or the time the keycap hits bottom? What if the switch closes before the cap hits bottom: then we are getting a latency figure that looks better than it really is.
I've had a keyboard like that and with it, xterm (and nothing else) felt like it was displaying the characters even slightly before I had pressed them. It was a weird sensation (but good)
Yes, I know this feeling, it's like typing on air. The Windows Terminal has this same feeling. 8 years ago I opened this issue https://github.com/microsoft/terminal/issues/327 and the creators of the tool explained how they do it.
xterm in X11 has this feeling, ghostty does not. It's like being stuck in mud but it's not just ghostty, all GPU accelerated terminals on Linux I tried have this muddy feel. It's interesting because moving windows around feels really smooth (much smoother than X11).
I wish this topic was investigated in more depth because inputting text is an important part of a terminal. If anyone wants to experience this with Wayland, try not booting into your desktop environment straight into a tty and then type. xterm in X11 and the Windows Terminal feel like this.
Nerve signals yes. I just try them side by side, usually running vim on both terminals and measuring how it feels. If you can feel difference, the latency is bad.