Kabuu Video Downloader is a freeware multithreaded YouTube downloader for audio and or video.
You can easily copy a link into the app from your clipboard to get started.
Before you download the file, you can choose the format, subtitles, and if you want to convert. Mp3 isn't, not supported, only MP4, Opus, and Webm.
Click Download or Download All to download the files you have added.
A handful of settings are worth looking at, including the number of parallel downloads, preferred format, directories, and even your YouTube username and password, although insecure.
Kabuu Video Downloader is free and simple to use for anyone.