most of these require logout/restart to take effect
# Enable character repeat on keydown
defaults write -g ApplePressAndHoldEnabled -bool false
# Set a shorter Delay until key repeat
I've done the same process every couple years since 2013 (Mountain Lion, Mavericks, High Sierra, Catalina) and I updated the Gist each time I've done it.
I kinda regret for not using something like Boxen (or anything similar) to automate the process, but TBH I only actually needed to these steps once every couple years...