Here's a couple of links discussing terminal latency. When I first read it I was using KDE Neon and terminator and perturbed that my PC ran a degree or two hotter than it did with Mint Cinnamon. My latencies with various terminals pretty well matched the article (including the new Rust terminals). Since then I discovered the joy of xterm, how much desktops and window managers affect latency (xfce is faster than mate but i3 is faster than both; and dwm is faster still), and finally that devuan is faster than debian and that obarun is the fastest I've found so far (to be fair I suspect that may be an Arch kernel thing).
With Obarun I see latencies of about 0.6 ms in xterm and 0.8 ms when running tmux in xterm using a middle of the road pc (Ryzen 5 3600).
https://lwn.net/Articles/751763/
https://news.ycombinator.com/item?id=19443076
https://blog.blahgeek.com/best-terminal-emulator/
Regarding getting typometer running, for Obarun I needed to use the Arch's java 8 despite using 11 on Debian so I removed later Java's and `sudo pacman -S jre8-openjdk` should do it.
~ > java -version
openjdk version "1.8.0_292"
OpenJDK Runtime Environment (build 1.8.0_292-b10)
OpenJDK 64-Bit Server VM (build 25.292-b10, mixed mode)
and thanks techore.