Piracy: ꜱᴀɪʟ ᴛʜᴇ ʜɪɢʜ ꜱᴇᴀꜱ

Hi friends,

I've been using yt-dlp to download a few things off of YouTube Music, and I just wanted to ask a few questions about best practice. Right now, I've just been doing it this way:

yt-dlp -f bestaudio -x

I've found that has usually downloaded .opus files (though, .m4a as of late—anyone know why this is?), but, I was wondering (for the sake of compatibility with different music players), do I lose anything by passing --recode mp3?

Also, about losing the .opus files, I got this output when I ran yt-dlp -F on a link:

|ID |  EXT   RESOLUTION FPS CH |    FILESIZE  TBR PROTO | VCODEC         VBR ACODEC      ABR ASR MORE INFO
--------------------------------------------------------------------------------------------------------------------------
233 mp4   audio only        |                  m3u8  | audio only         unknown             Default
234 mp4   audio only        |                  m3u8  | audio only         unknown             Default
249 webm  audio only      2 |     1.30MiB  64k https | audio only         opus        64k 48k low, THROTTLED, webm_dash
250 webm  audio only      2 |     1.64MiB  81k https | audio only         opus        81k 48k low, THROTTLED, webm_dash
139 m4a   audio only      2 |  1019.36KiB  49k https | audio only         mp4a.40.5   49k 22k low, m4a_dash
251 webm  audio only      2 |     3.03MiB 149k https | audio only         opus       149k 48k medium, THROTTLED, webm_dash
140 m4a   audio only      2 |     2.64MiB 130k https | audio only         mp4a.40.2  130k 44k medium, m4a_dash

Any insights as to why I'm getting that throttling, and why it's downloading m4a instead of opus? Is it even that much of a difference? Is there some option I can pass to yt-dlp to avoid this?

Any help is much appreciated!