A barrel of worms, I said? More like a 10 yard dumpster full of 'em!

I don't know if it's the case, but it appears as if VLC was developed for Windows and ported to OS X/macOs...except for the documentation, which seems to be totally Windows oriented.

And further, the linked "solution" was posted 4 years ago, so I can't be certain whether VLC has changed in the interim or the post is incorrect.

Quote:
The option is present in VLC > Preferences (Click Show All) and you will find it under Video > Filters > Rotate. Then you can choose it from Window > Video Filters.

I arrive at the same dead end as you did with the preference; there's no apparent way to make use of the angle setting, although there may have been a way to use it with Window > Video Filters.

Unfortunately, though, Window > Video Filters either never did or no longer exists.

There is, however, Window > Video Effects > Geometry, which offers only these limited options.

Also unfortunately, while you can make a setting stick for a particular video in Windows, as far as I can tell, there's no way to do it in OS X/macOS.

Your options in OS X/macOS appear to be
  1. reset your selection each time you play the video, or
  2. click the "Apply profile at next launch," box, which will set your selection as a permanent pref for ALL future videos,
neither of which seems particularly useful to me, nor do I think that either is what you're looking for.

Somewhere in the jumble of letters and punctuation that comprises VLC's documentation I found a statement to the effect that while VLC can be used to "manipulate" videos, it's real purpose is to play them, and you may be best off using another app for "manipulation."

I think the suggestion is right on the mark!

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire