This is a slightly updated version of https://robert-chalmers.uk/2018/04/27/extracting-downloading-subtitles-from-netflix-movies-for-ff-learners/.

I recommend going through that tutorial and if it doesn't work this may address some issues.

I am using the film "El Hoyo" in this tutorial.

Make sure that when you click on the Tampermonkey chrome extension it is shown as "activated" as opposed to "disactivated". Then click on "Dashboard" and make sure "Netflix - subtitle downloader" is toggled to activated as well.

Navigate to Netflix and select the film or show episode you want to get the subtitles for.

• At the top of the page a "Netflix subtitle downloader" button appears.
• Hover over that.
• For "subtitles format" I picked "prefer DFXP/XML" as there is no .srt option available.

The DFXP/XML file will end in ".dfxp".

Then

• Go to https://gotranscript.com/subtitle-converter
• Upload the .dfxp file
• Select "subrip (.srt)"
• Hit "convert"

If you open the .srt file, you may notice <i> and </i> tags. To get rid of them follow the following instructions although it is probably not super important that you do so depending on your use case.

• In a command line or the "Terminal" application on MacOS use/paste the following commands (where "El.hoyo.WEBRip.Netflix.es-ES[cc].srt" is the .srt file name for the movie El Hoyo in this case but for you it will most likely be different)
  • sed -i -e 's/<i>//g' El.hoyo.WEBRip.Netflix.es-ES[cc].srt
  • sed -i -e 's/<\/i>//g' El.hoyo.WEBRip.Netflix.es-ES[cc].srt

Then follow the original instructions of going to
https://anatolt.ru/t/del-timestamp-srt.html and then
https://www.browserling.com/tools/word-frequency if you wish.