I actually went on a deep dive when I encountered this project a few weeks ago.
It seems a lot of the magic comes from Respira (https://github.com/jhbruhn/respira), there were already open source softwares to avoid using the subscription app.
Also the $300 price was probably secondhand/on sale because that machine is usually 499, not 300.
Still a cool project, but you'd think this was reverse engineered from scratch from the description whereas this is more like a downloader wrapping yt-dlp
It's available for $303 right now on amazon. I also reverse engineered the protocol from scratch using PacketLogger. It looks like my agent also used Respira to verify the implementation. With that said, the entire app was built with AI.
Maybe I'm missing something, but this repo seems to be 2 days old so you cannot have encountered it a few weeks ago. There were perhaps a few short form videos showing the project in development, but that seems a bit shallow for a deep dive into the specifics of where the magic comes from.