1. Tell them to fuck off, which may or may not work in any given context
2. Play the music in the browser and then hop back to Mixxx in time (dangerous)
3. Downloading the song via 'yt-dlp -x --audio-format mp3 --audio-quality 0 <URL>', fixing the questionable metadata (optional) and then loading it into Mixxx (cumbersome)
It would be cool if you could just paste the URL into Mixxx, have it cache a local version, render the waveform, store it in a special temp crate or what and then you can play it. But I guess yt-dlp isn't the most stable dependency...