There is no universal now

In special relativity, whether two distant events are simultaneous depends on the motion of the observer. Nature does not supply one shared present.

Einstein’s 1905 paper puts the knife in the ether and in the absolute present together. Synchronise clocks with light, the way you must, and a platform moving relative to you will not agree which distant ticks were simultaneous. Both platforms are right. There is nothing else to be right about.

The disagreements are tiny at walking speed and enormous at interstellar distance. A definition of ‘everything that is happening now’ across the galaxy includes, for a fast enough traveller, events you would call next year and events you would call last year. Causality survives. The cosmic present does not.