The current understanding in theoretical physics is that spacetime and the Standard Model of particle physics are part of our current framework for describing the fundamental aspects of the universe. However, there is ongoing research and exploration into theories that aim to go beyond these concepts and provide a more fundamental description of reality. These theories are often referred to as "theories of everything" or "fundamental theories."
One notable example of such a theory is string theory. String theory proposes that the fundamental building blocks of the universe are not point-like particles but tiny, vibrating strings of energy. It suggests that spacetime is not fundamental but rather emerges from the interactions of these strings. String theory attempts to unify all known fundamental forces, including gravity, within a single framework. However, string theory is still an active area of research, and many aspects of the theory are yet to be fully understood and tested.
Other approaches, such as loop quantum gravity and causal dynamical triangulation, also seek to provide a more fundamental description of spacetime and gravity, often departing from the continuous and smooth picture of spacetime in general relativity.
Additionally, there are various ideas related to the nature of dark matter, dark energy, and the unification of all fundamental forces, including gravity. These ideas often require extending our current understanding and could potentially reveal more fundamental aspects of the universe.
It is important to note that while these theories offer promising directions for exploring fundamental physics, they are still in the realm of theoretical research and have not yet been experimentally confirmed. Discovering a more fundamental description of the universe beyond spacetime and the Standard Model remains an active and ongoing pursuit in theoretical physics.