Here’s what I don’t understand. It all seems like a limitation based on the assumption that the observing ship is not moving at all. You can’t travel the speed of light relative to me because it would look like you’ve stopped accelerating.
What if the observing ship is moving half the speed of light, and the other ship is moving in the opposite direction at half the speed of light? Relative to each other, they are both traveling the speed of light now. I am definitely missing something here.