Subtitles are, in general, a pain to deal with.
Tracks created with the "forced only" (solo forzato) box checked are almost always empty, because the authors do not use the forced flag. The only track you will end up with is the "main" track above it.
As for "working", is the track that was extracted flagged as "default" by MakeMKV? While most software and hardware players I have worked with ignore the "default" flag, there are some that use it. If you have one of those, you should still be able to select a non-default track from the subtitles menu of the player.
If this is the case, you will need to create a profile that sets the default flag for the extracted track. If you were processing the file with handbrake after ripping, this is simple, but it CAN be done in MakeMKV... But I can't tell you exactly how to do it without digging through forum messages. Hopefully others know it and can post it.
Basically it involves making sure your favorite language's subtitles get listed first, then setting the first subtitle track as "default". These are actually the OPPOSITE of the settings I use, so I might get it wrong if I tell you how to do it.

I use handbrake to process everything, so I use the subtitle controls in it to sort things out.