I finally took some time recently to cobble together a set of bash scripts to allow me to download local copies of videos from youtube, heavily piggy backing off the jbergknoff/youtube-dl Docker image and the associated youtube-dl project.
You can add the following bash functions to your own env files (I’ve a post on my own setup in the works).
Then assuming you have Docker running you can download a Youtube video as follows:
youtube-dl https://www.youtube.com/watch?v=WPsu4OH9hsk ~/brooklyn-gource.mp4
You can omit the target file and it will download to