Comment by banana_giraffe

You can use yt-dlp to get the transcripts. For instance, to grab just the transcript of a video:

    ./yt-dlp --skip-download --write-sub --write-auto-sub --sub-lang en --sub-format json3 <youtube video URL>

You can also feed the same command a playlist or channel URL and it'll run through and grab all the transcripts for each video in the playlist or channel.