That gets me the subs in some usual complicated format? It's a bit of work to extract the actual text from that.

To get youtube subs in .srt format this gave me some limited success:

    yt-dlp --convert-subs=srt  --write-auto-sub --write-sub --sub-lang "en,en-us,en-GB,automatic-caption-en" --skip-download  "https://www.youtube.com/watch?v=1OfxlSG6q5Y"

Behind the scenes yt-dlp is downloading the subs in .vtt format than using ffmpeg to convert those to .srt. Depending on your situation the original .vtt format might be fine.