A universal frame is totally in the cards. As I understand it, we have no "real evidence" one way or the other, though the scientific community has fully embraced Einstein. Your description sounds like Lorentz Aether theory, which is something I've heard talked about. Based on the idea that Lorentz transformations are "more fundamental", I think. All known physical phenomena obey Lorentz invariance, after all.

There's a saying: "FTL, relativity, Lorentz invariance. Pick any two." The one thing that can tell us one way or the other is FTL phenomenon that we can experiment with.

I'm on the fence between universal frame or not. Truthfully, I haven't looked too deeply into it. The universe shows some suggestion of an in-built causality protection, specifically through Visser collapse.

In Einsteinian space, wormholes attempting to break from "safe" alignment, forming a CTC, experience a super-resonance of vacuum fluctuations due to vacuum polarization, destabilizing them both before a CTC can ever form. The same mode of collapse would likely apply to Alcubierre-like drives, too.

In short, FTL + causality protection looks like it could work in a relativistic universe, just as well as one with Lorentz invariance and a preferred frame.

There just isn't a way to distinguish which one we're in yet, if either.

The AMERICAN scientific commuity has embrced Einstein, to the point where the physics departments of AmericanUniversities refused to hire or comnsider any professors with any other perspective. That is part of the reason why America has not won a Nobel prize in physics in decades. All of the advancements are in areas that have left Einstein far, far behind.

A really intersting viewpoint arose from Zeno's arrow paradox that tried to prove motion was impossible. plato.stanford.edu/entries/paradox-zeno It posits that what is reallyhappening is like stop-motion animation, whare time is really the transition from frame to frame. In this regard, the universe is like an entirely pixilated space whare the pixels are the size of a Planck length, and each pixel in the universe changes from frame toframe based on probability.

In this model. relativity is impossible because motion is impossible. And the transition from one frame to another only depends on the state of the last frame and probabilistic 'actions' on each quantum pixel. Therefore 'time travel' can not exist because only two frames ever exist - the previous frame and the new frame.The constant 'c' is really just the frame rate. Nothing can exist between frames - there is either one frame at one instant of time, and the next frame at the next instant.

Therefore the units of 'c' are frames per second. Since every pixel experiences the same frame rate, 'c' is constant everywhere. However nothing prevents a pixel of information from 'decohering' anywhere in the space, therefore no real limit on speed if speed is defined as 'number of pixels apparently shifted per frame'. But if the fastest contiguous speed is defined as the transformation being limited to no more than one pixel transversed over per frame, then 'c' determines the fastest speed.

But if a pixel transverses more than one pixel between frames, it is no longer contiguous with the pixel beside it, unless both pixels transverse in the same direction by the same number of pixels, an unlikely but still probablistic possability and whatever 'object' the combined pixels formed is no loger contiguous, unless it was all combined into one quantum equation. The trick is the algorythm of the probability function of pixels between frames, like a 3D game of life conwaylife.com.

Incidentally, there is nothing inherently wrong with backward causality in a purely deterministic world. If B comes before A, and B leads ot A, then we say that B causes A. But in a deterninistic world, the fact that we have A means that B MUST HAVE existed. Therefore, A caused B, in the sense that without A there could be no B. But C came befire B, and B is dependent on C having occured,Therefore the existence of B means that C muist have occured, B caused the existence of C to be mandated.

So if the current world time was caused by all of the events of the time just before it, then the current world caused the just-previous world to be. And so on and so on. If something causes something else in the future, then there HAS to be backwards causality - what existed now had to have caused what is to be. That in essence is the grandfather paradox of time travel. The presentg caused the past to be what it was.