[Y_Y]

> speed basically borrows energy from time

This sounds cool, but I don't think it has explanatory value. It's true that moving close to the speed of light will mess with your intuitions about the passage of time and give you things like the Twin Paradox. But there's nothing special about time there, it also makes things shorter by Fitzgerald contraction.

You can't be in the future, for example. The point of relativity is the equivalence of reference frames, it's not like the space traveller's clock is wrong and the stayhome's clock is correct, it's that humans who never travel at speeds close to the speed of light don't expect that two good clocks could ever disagree.