Alternatively you can view it on invidious ( https://invidio.us ) which doesn't track you, simply replace all the youtube or youtu.be stuff with invidio.us, you can keep the unique video identifier though.
Hope this helped!
Oh, quick tip I learned, if you like full 1080p then you can download the video and audio seperately and then stitch them together with ffmpeg using the following command:
ffmpeg -i video_file -i audio_file -c copy output_file_name
also, if you need subtitles youtube-dl --all-subs is useful, which then you can weave into the above outputted file too:
ffmpeg -i file -i subtitle_file -c copy output_file :)
A friend of mine did an automated download of all youtube videos in his firefox history, I think by dumping the sqlite database that contains firefox's history. Should be only a couple of lines of shellscript.