To update my own answer: You can use shortcuts to run a yt-dlp on youtube videos, which you find from an RSS feed of the youtube channel. Requires 'a-shell mini', shortcuts app, ffmpeg, and some patience.

you could probably do this over iCloud. Set your phone to download all files, run the ffmpeg script on your computer and place the files in iCloud. If you need a to open the iCloud app to force a sync, use Shortcuts to open the app at 3am or whatever.

If you're on Android, a program like Tasker could and Google Drive could likely accomplish the same results.