I have had very similar issues, although have not used subtitles. Have you tried Read&Write accessibility software? I got it through disability services at my job, but see that it is available as an app through Google Chrome. I don't know the cost. I have found it to be very helpful.
It highlights one line of text at a time, and simultaneously does text-to-speech; i.e. it audio reads the line. It works on documents and webpages. It also does speech-to-text.