yt-dlp -f bestaudio/best --extract-audio --embed-metadata --embed-thumbnail --recode opus --audio-quality 0
It does recode to opus but since the bestaudio is usually in that format already, you don’t need it most of the time. You can skip the –recode opus part if you want to. I keep it because I like having a “uniform” collection. You can probably change the bestaudio/best part to simply bestaudio without losing much as well.