I found an interesting article about trollsubs, which I guess are fansubs made with a contemptuous flare. https://neemblog.home.blog/2020/08/19/the-lost-art-of-fan-ma...
Tangent: I'm one of those people who watch movies with closed captions. Anime is difficult because the subtitle track is often the original Japanese-to-English subtitles and not closed captions, so the text does not match the English audio.
The conversion process from pronunciation to intended text is not deterministic either, so it probably can't be solved by "simply" generating all-pronunciation outputs. Maybe a multimodal LLM as ASR/STT, or a novel dual input as-spoken+estimated-text validation model could be made? I wouldn't know, though. It seemed like a semi-open question.