The easiest way is to use the yt-dlp tool (a newer and better version of the old youtube-dl). It works great with long content like audiobooks.
sudo apt update
sudo apt install yt-dlp
(or the latest version:)
pip install -U yt-dlp
yt-dlp -x --audio-format mp3 "<URL>"
This:
-x → extracts audio only--audio-format mp3 → converts it to MP3yt-dlp -x --audio-format mp3 --audio-quality 0 "<URL>"
yt-dlp -x --audio-format mp3 -o "%(title)s.%(ext)s" -N 4 "<URL>"
-N 4 → parallel downloading (faster and more stable)yt-dlp -x --audio-format mp3 --embed-thumbnail --add-metadata "<URL>"