That's not what I mean. The site you linked is about how to make a mouse-first website more keyboard friendly, but what I would like to exist is a mature keyboard-first guide.

I mean something like this (my wip keyboard-first file manager): https://ibb.co/G3WBW5C1

The hard part is, there seems to exist no UI & UX design language I can follow to create a nice keyboard-first app, so I have to think through everything (which is fun but tiring).