Increase key repeat rate on macOS
Settings: System Preferences » Keyboard » Key Repeat/Delay Until Repeat
Use the commands below to increase the key repeat rate on macOS beyond the possible settings via the user interface. The changes aren't applied until you restart your computer.
defaults write -g InitialKeyRepeat -int 10 # normal minimum is 15 (225 ms)
defaults write -g KeyRepeat -int 1 # normal minimum is 2 (30 ms)