All of time is an illusion. I mean yes, time is constant but our units of measurement are 100% made up. TZs are just as much of an illusion as picking DST/Standard year round, clocks are only "true" because we say they are. If you want to live in a world where time is not an illusion then drop all measurements except seconds, measure things in mega-seconds/kilo-seconds/etc, and remove TZ/Hours/Days/Weeks/Months/Years. All of those measurements only make sense on Earth. Once/if we become a starfaring species then this will get even more complicated. Maybe "day" will still make sense if only because we are used to that circadian rhythm but week/month/year? Not worth much in space.