The cause that makes space and time relative in our universe must lie outside the universe

The cause that makes space and time to be relative in our universe must lie outside our universe. Otherwise we will have to admit that there was a time when they were not relative, but absolute.

We know that space and time are relative in our universe. But what is the cause that makes them to be relative? Let us say that A is the cause that makes space and time relative. Now regarding A there are two possibilities here: 1) This cause lies within space and time and 2) it lies outside space and time. Let us suppose that the cause A lies within space and time. But this possibility is having one inherent problem in it. We say that A is the cause that makes space and time in our universe relative, and we also say that A lies within space and time. So when A made its first appearance within space and time, it also caused space and time to be relative for the first time. From that time onward they have remained relative so far. So from this it can be concluded that before the appearance of A within space and time, space and time were not relative; they were absolute. But will the scientists agree that space and time were not always relative, that they were not relative from the very beginning of their existence? But if they say that space and time were relative, and are still relative, from the very moment they came into existence, then they will also have to admit that the cause that makes space and time relative in our universe was already there prior to the moment space and time came into existence, that is, prior to the beginning of our universe.

The only solution to this is that the appearance of space, time and A from the big bang must have to be simultaneous. But will it be scientifically correct to say that all the three of them appeared simultaneously from the big bang?