It's not as difficult as you might think. Now the YouTube Music service has appeared, but it is not available in many countries. Thus, you can find workarounds for downloading and listening to music from YouTube. For example, you can use aac converter, which can convert video to audio files without downloading music. Online services are unreliable because the data is not encrypted, but this online converter does not store user data in the cloud. So I trust this service. I hope I was able to answer your question.