> a modern audio codec at 320kbps bitrate is more than good enough.
MP3 V0 should already be, and is typically smaller.
That said, it does depend on the quality of the encoder; back in the day a lot of MP3 encoders were not very good, even at high quality settings. These days LAME is the de-facto standard and it's pretty good, but maybe some others aren't(?)
Hell, modern audio codecs (opus and AAC, but not the ffmpeg opus/AAC encoders) are transparent at ~160-192k. MP3 is a legacy codec these days, and generally needs ~30% more bitrate for similar quality.
MP3 V0 should already be, and is typically smaller.
That said, it does depend on the quality of the encoder; back in the day a lot of MP3 encoders were not very good, even at high quality settings. These days LAME is the de-facto standard and it's pretty good, but maybe some others aren't(?)