Well there such a thing as time but it should be thought of as the “eternal now” in which God operates where past present and future are all the same. We know that the speed of an object affects the passing of time relative to that object as opposed to what happens to other fixed objects on Earth. The techs do have to put in correction algorithms in orbiting space craft as their speed relative to objects on earth makes them several seconds behind with increased compounding of such time errors unless the the correction factors are programmed in. The ratios are such that if such craft approached the speed of light, then time goes towards “nowness” while time on earth passes in a flash. But it takes enormous amounts of energy for an object to reach the “nowness” of zero time. Hence increased entropy of the universe as energy is drawn from it for a given object to hit light speed and the nowness state of zero time.
I think you are right in one sense about time being an artifical construct. It is a tool to help us understand rates of changes and proportions in our work and in our lives in this backdrop of entropy we exist in. Our standardized measurements of time may not be the same standards used on some other hypothetical world but whether this world or that world the same laws of physics, as they pertain to the passage of time of particles accelerated to great velocities/ relative to a fixed point on on either world, would apply.
(I mean we understand the concepts, but balancing our check books is pretty-much the practical extent of our math knowledge).