You could do a lot more with this. Consider that the FF addon is a 'front-end': user options could include nightly updates (a must), audio only (mp3, flac, ogg, aac, opus, wav), streams: HLS->mp4, user url lists (it already does YT playlists).

Package yt-dlp 'full boat', with everything it needs: deno.exe, aria.exe, ffmpeg, ffprobe, all in it's own folder (all MIT or equiv). You already have a good start, take it the rest of the way.