It’s not a speed limit as such. You don’t go up to it and then find you can’t go any faster. It’s more like a horizon that you can never reach. Even in a flat spacetime model there’s plenty of “warping” in the Lorentz Transformation.
I recall that in FARMER IN THE SKY, I believe it was, the young hero questions the spaceship engineer what happens if you reach “almost” the speed of light and then go full blast. In the story, the engineer has no answer, only proving the author’s limited grasp of this subject.
The Lorentz transform doesn’t warp space in the way that the inflationary universe expanded, which was the point the poster I responded to was wondering about, having apparently found a contradiction. (”Can things move faster than light or can’t they?) I was trying to resolve that contradiction. I am well aware of the asymptotic nature of approaching c.