What is time, or more precisely, does time exist.
Time is like numbers, in fact, it is a subset of numbers, or better still, it belongs to the concept of numbers, or numbering system, it describes events.
Do numbers exist. The answer is a big NO with capital letters.
Yet, we use numbers every day, at school, shopping, etc. They are an invention of the human mind as they do not exist in nature, an invention that became necessary, initially, to communicate quantity, 1 sheep, 2 sheep, 3 sheep ..... etc.
As the use of numbers grew, they became more complex, developed its own logic structure, and generally, it was called mathematics, the study of numbers.
Because of certain events, the sun rises every day, the day yesterday is not the same as today or the day tomorrow. Living organisms, are born, stay alive for a certain period and then die, the human mind was forced to invent the concept of time, just like numbers.
However, later, tried to define it, more precisely. That is, which moment is past, which moment is now and which moment is future. And how about in between moments, is there really a time lapse - time ceases to exist, before it begins again.
To the point, including Albert Einstein, as some ancient Greeks, came to the conclusion, the past, present and future exist at the same time. The concept of time is an illusion but necessary to explain timely events.
...all of the above, in relation to your statement "I was considering the options, the flow of time as we see it is relative ....."
...and to be more succinct. An illusion just like the co-ordinates of an object's position.
As you were, probably, taught at school, we need three co-ordinates: xyz to define position, other argue the time as well.
If you were in space, how any combination of the above co-ordinates would identify, your position in space. Can you tell the position of the earth, say, an hour ago, in space. The space co-ordinates, in other words.