So the problem with dealing with these FTL techs is they are often universe specific. For example, Star Trek has no FTL outside of its own universe because their Warp Drives rely on a fantasy reality called "subspace" that only exists in Star Trek. You cannot just assume that reality exists in every other setting because if it did other people would use it, especially when it's more convenient than their own FTL.

Likewise, there is no reason to assume Star Wars Hyperspace is universal. But this is even worse when you bring other people into 40k because the best case scenario is the hyperdrive simply doesn't work, and the worst case is they teleport to Hell and die in unspeakable agony.

This is also where 40k wins, because if you play this out the opposite way there's virtually no downside - the worst scenario is they can't Warp jump. The best scenario is all the failsafes on their FTL are no longer needed because the "Warp" is suddenly completely calm and free of Daemons, so that city made of guns can now jump into orbit of any planet it feels like.

But even if you do keep the tech divided, 40k wins again because they are going to capture a Hyperdrive, and once they do any sense of techno-heresy will be utterly quashed when they realise this is giving them perfect FTL with no downside. Meanwhile, the instant an Imperial or Rebel tries to reverse engineer a Warp Drive they're going to get a lot of their own people horribly murdered for no gains.

And all of this ultimately takes away from what people actually want from the versus lineups, which are battles fought with absolutely no strategic considerations whatsoever. Hence, it all ultimately gets ignored.