Yeah, it's probably best to use some online converter or something. This seems unnecessarily difficult to install (I'm giving up after a couple of tries), not to mention that doesn't seem to be abandoned.
If you're comfortable with the command line, you can use yt-dlp directly from there. That's what I use and it's frankly a lot easier than this:
@51gertrude You can also try downloading "Parabolic" from the software store. Is another frontend for yt-dlp, and seems fairly up to date: