"Extract to SRT", however it doesn't seem to work well with Prime Video, Streamfab is not creating any SRT files.
mlim
I have been using “Extract to SRT” for over a year
and have never had a problem (with amazon content).
I should mention that I usually only select one language (forced).
Recently a user reported “out of sync” with remux into file on forced subtitles in USA - 
here