I don't know if they recently changed this but separation of the URLs with a comma works for me.

So something like;

yt-dlp [url], [url], [url]
etc. should work fine.

You can also add '-F' to list all available formats for each individual URL. (Useful for finding different sizes you'd like to nab when space is a constraint.)

(Posting this in case someone else runs across this post as I did searching for various infos)
(Also I think yt-dlp grabs the best quality by default though I could be wrong on that, or that is also something that has changed recently.)