THIS is a good suggestion; I’m not aware of any decentralized search that also specifically helps find subtitles.

Apps being able to search opensubtitles.org\com via the API, are a great convenience, but I’m not aware of any comparably convenient way to submit subtitles. Currently, it’s a bit of a pain, just to try & help. (For instance, .srt files with perfectly standard formatting, rejected for no discernable reason whatsover, requiring upload in .ass format instead.)