Parent’s is more complicated, but this simple script may be a good place to start. In this case, I follow a channel that posts new music videos for discovery. This automatically downloads (just the audio) using yt-dlp to a local directory. It could easily be modified to download the video (just change the -f flag). I run this with cron once a day.

https://gist.github.com/line72/ceef5402881d6d3ae732e7b7c9cbf01b