This allows you to download all true qualities available - wonderful.

I seems to be yt-dlp integrated into FF and a simple, clean app. (No need to use the console/FFMPEG finicky combo.) I highly recommend getting the free app. I was hesitant at first, but there are no catches. Good set of options, and you don't even need to go to the actual video, you can copy a URL and the app automatically reads it. You can even que up multiple videos!

It can put a heavy load on disk bandwidth and processor, depending on the size and format you choose. Just be aware of that.

My only minor nitpick is that it doesn't have more file save location options, like setting a default, or use last folder. Oh, and the infinity sign that comes up over the download % worried me - i thought it was stuck, but it wasn't.
--- I'm so thankful i found this. Thanks unidl!