the outcome of the “invisible ship”

Balance of Terror?

I think so, I consider myself a ST fan, have watched almost everything two exceptions, one is Discovery I dropped on season 2-3 don't remember exactly that was not fun to watch, and TOS I tried to watch it, but I can't stand it, it's too old for me, so I know nothing of Balance of Terror, yeah, I know there are some Romulans and it's supposed to be the invisible ship, nothing else.

the theory about the Vulcan Cadet was true

Wait, is there a theory she’s a Romulan or something?

In the other threads someone suggested that the Vulcan Cadet that left Starfleet is a Romulan spy. I am all in at this moment, it could be a great AHA! moment in the future.

About Sybok, again, no TOS background here, but the story about Captain Angel, and how they trick Pike was so great... and never had a payback or a conclusion that is a shame.