A couple of months ago, I created a small application called "SUPfoe", that allows you to extract the "FORCED" subtitles from the .sup subtitle files that you have extracted from your BD/UHD discs. This works on windows only and .net framework 4.5 or higher is required (so Win10 users should be fine).
It is a "1-click" application and is simple to use.
Step 1: Run the SUPfoe.exe
Step 2: Either click the "OPEN" button and select a .sup subtitle file OR drag 'n' drop a .sup subtitle file onto the 'source' textbox.
That's it! The 'Info' window will let you know how many subtitles are in the file and how many are flagged as 'forced' (if any). At the same time, if there are any 'forced' subtitles, the application will extract them to a file in the same directory as the source file.
Here is the thread for the download: https://www.makemkv.com/forum/viewtopic.php?f=6&t=20964
For those of you that want the FORCED subs, and don't want to use "bdsup2sub", feel free to give it a try and let me know (in that thread!) if you have any issues.