Finding the right subtitles for forced tracks

What advice do people have for finding subtitles with things that require forced subtitles? Things like Lord of the Rings (where they talk in Elvish) or the Star Wars movies (different alien dialects) often require subtitles. Sometimes movies are entirely unwatchable without them. And for some reason, they aren't baked directly into the video file. This means that opening them in Plex or VLC by default does not display what's being said. This has led to many frustrating situations where I'll be watching something with a group of people and somebody starts speaking in another language. We're all left wondering "Are we supposed to understand what is going on here? Or is it supposed to be a mystery?" And then after 45-60 seconds of them talking in another language, it becomes pretty clear that there are supposed to be subtitles here, and they're just not there.

How are you supposed to know when there should be forced subtitles and when there shouldn't be? How are you supposed to find which one is the correct one where there are often so many options in Plex and VLC that say "English?" Most of them just play subtitles throughout the entire movie, which is irritating for most people we watch movies with.

I've tried messing around with open subtitles, but even that has been heavily hit or miss, and the last few days as I've tried it, the pages won't even load beyond the search.

Any advice?