How to preserve audio

Prerequisites
 Download yt-dlp with the package manager of your choice. Examples: 
sudo wget https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp -O /usr/local/bin/yt-dlp
sudo chmod a+rx /usr/local/bin/yt-dlp
python3 -m pip install -U yt-dlp
yay yt-dlp
sudo apt install yt-dlp
sudo nala install yt-dlp
Download ffmpg with the package manager of your choice. Examples:
yay ffmpeg
sudo apt install ffmpeg
sudo nala install ffmpeg
Download optional dependencies if necessary from here 
Make a directory where your config files will sit
Create your first config. Example:
# Uses best audio
-f bestaudio
# Don't stop even if not perfect
-ciw
# verbose
-v
# Extracts the audio
--extract-audio
# Uses best quality
--audio-quality 0
# Makes it a mp3
--audio-format mp3
# Thumbnail
--write-thumbnail
--embed-thumbnail
# Embed info json
--write-info-json
--embed-info-json
# Metadata
--embed-metadata
# Description
--write-description
# Mark Video as watched. May count towards view count.
--mark-watched
More file examples can be found here

Time to archive
How to archive an entire YouTube channel
Create a directory where you want your files to be
Download or create the necessary files to create directories, move files and download videos. Examples:
#!/bin/sh
if [ ! -d "audio" ] ; then
mkdir audio && mkdir metadata && mkdir thumbnails && mkdir descriptions && echo "Created directories"
fi
#!/bin/bash
if compgen -G "*.mp3" > /dev/null ; then
mv *.mp3 audio/ && mv *.webp thumbnails/ && mv *.description descriptions/ && mv *.info.json metadata/ && echo "Moved files"
fi
#!/bin/bash
yt-dlp --config-location /srv/dev-disk-by-uuid-fa1e36be-9ccc-4549-8734-fe6117b30317/croni/andre/andre/Archive/yt-dlp/yt-dlp_music.conf --download-archive youtube_backup_downloaded.txt --yes-playlist 'https://youtube.com/playlist?list=PLeEbifL6wH9okMEgTQP459RcTrjBWkF_b'
Execute these files however you want. I personally would recommend to set up a cron job to periodically download new videos. Example:
nohup ./backup.sh > backup.log &
If you execute the command above your only way to know what yt-dlp is currently doing is to tail the log with 
tail -f backup.log
 While waiting for the download to finish you can create the necessary directories to organize all your downloaded files. Example:
#!/bin/sh
if [ ! -d "audio" ] ; then
mkdir audio && mkdir metadata && mkdir thumbnails && mkdir descriptions && echo "Created directories"
fi
When the download is finished an you created the directories it is time to move them to their dedicated directory. Example:
#!/bin/bash
if compgen -G "*.mp3" > /dev/null ; then
mv *.mkv audio/ && mv *.webp thumbnails/ && mv *.description descriptions/ && mv *.info.json metadata/ && echo "Moved files"
fi
You successfully archived an entire YouTube channel 🚀
Tips
Make your files executable with 
sudo chmod +x file.sh
You can execute the files with 
./file.sh
This guide can be adapted to download playlist and even single videos
If you only want to download one video then remove  
--yes-playlist