I'm the author of the Java GUI for hacktv mentioned in the OP. Good to see hacktv getting around!
The reason youtube-dl doesn't work is because YouTube have been throttling third-party applications for a while now. yt-dlp implemented a workaround by spoofing an Android app in the user agent, but this has not been merged upstream. In fact, development of youtube-dl seems to have more or less stalled. I may remove youtube-dl in later releases (and require yt-dlp) to avoid confusion.
Also, I managed to blow the amp in my HackRF just by briefly brushing the transmit aerial against the receive one. It's very fragile, hence why I have the warnings there.