https://www.youglish.com is also a sort of search engine for YouTube captions, though mostly aimed at short phrases.
I searched for my YouTube username and then for the exact title of one video I posted and it didn't find either one.... instead it said the title of my video was not true because it didn't interpret it correctly (but it didn't link to the video).
I'll look into it, could you send the request to askutubeai@gmail.com?
not sure what else you need.... don't you keep logs?
Your request wasn't logged. This can happen sometimes if the request wasn't completed.