Einstein's theory of relativity does indeed treat time as a dimension, just like the three spatial dimensions. According to this theory, the concept of spacetime emerges, where time is combined with the three spatial dimensions into a four-dimensional continuum.
If a creature were able to travel in four dimensions, it would have the ability to move freely in the additional dimension of time, much like we can move in any direction within the three spatial dimensions. This hypothetical creature would have the ability to navigate both backward and forward in time, similar to how we can move in any direction within our three-dimensional space.
Now, as for the question of whether the future is as real as the past, it's a subject of philosophical and scientific debate. In the framework of Einstein's theory of relativity, time is considered to be a dimension that is fundamentally on par with the spatial dimensions. However, the flow of time is experienced in a particular direction, often referred to as the "arrow of time." We perceive this arrow of time as moving from the past to the future, and our experiences are rooted in this perception.
The past is typically considered as fixed and unchangeable because it has already occurred, while the future is seen as uncertain and open to possibilities. From this perspective, the past appears more "real" because it has already happened and left a trace in the present. The future, on the other hand, is not yet determined and can be influenced by various factors.
However, it's important to note that the nature of time and its philosophical implications are still subjects of ongoing research and discussion. Different theories, such as quantum mechanics, bring new perspectives and challenges to our understanding of time. So, whether the future is as real as the past is still a topic of exploration and interpretation.