How would we know if time did not exist the same or at all out there?
Observation. General Relativity predicts that time exists throughout the universe. General Relativity makes many predictions about what we should observe if that is true and, by golly, when we do the observations we see what GR predicted. E.g. gravitational redshift observed in white dwarf stars or the change in orbital period of PSR J0348+0432. There's loads more.
You are, of course, welcome to provide an alternate theory that squares with our millions of observations. Many people far more educated than you have tried. They have all failed.