Don’t you think saying “they can go FTL by building engines that go FTL” is not very scientific?
That isn’t an actual scientific explanation.
But that’s not the point of Star Wars. Sure a lot of stuff that is now Legenda did try to make a bit more sense of things. But never too much, because it would take away the magic of it.
It feels like a medieval fantasy world of knights, dark wizards (and racism I guess), but in space. Too much science would lose the fairy tale vibes.
It’s like expecting Dune to explain the physics behind the “Voice”. Dune is supposed to be this incomprehensible and distant tale, like reading from the first papyri from Egypt. It’s supposed to be mysterious and familiar but alien. Diving into the “science” of things in the way we understand science would kill the vibe.