The concept of the expansion of the universe can be a bit counterintuitive. When we say that the universe is expanding, it means that the distances between galaxies, clusters of galaxies, and other cosmic structures are increasing over time. However, it does not mean that everything is moving away from a specific point in space or that the universe is expanding "into" anything.
The Big Bang theory describes the early stages of the universe as an extremely hot and dense state. According to this theory, the universe has been expanding since that initial hot and dense state. However, it is important to note that the Big Bang does not represent an explosion that occurred at a specific point in space. Instead, it was an expansion of space itself.
In the context of the expansion of the universe, we often refer to the concept of cosmic time, which represents the passage of time since the Big Bang. As cosmic time progresses, the universe expands. So, the further back we go in cosmic time, the closer we get to the initial hot and dense state of the universe.
To answer your question directly, the hot Big Bang is not in the future. It is a concept that represents the early stages of the universe, and as we look back in cosmic time, we approach that initial state. The expansion of the universe does not imply that the Big Bang is in the future, but rather that the universe has been expanding since that early state.