No, it is not correct to say that all proposed theories of everything (TOEs) are quantum field theories (QFTs). While quantum field theories are important frameworks in theoretical physics, particularly in describing the behavior of fundamental particles and their interactions, they are not the only type of theory that can be considered as a TOE.
A theory of everything is a hypothetical framework that aims to unify all fundamental forces and particles in nature, including gravity, within a single coherent framework. Such a theory would provide a comprehensive understanding of the universe at the most fundamental level. While some proposed TOEs do involve quantum field theories, there are also other approaches.
For example, string theory is a prominent candidate for a TOE that goes beyond quantum field theory. It suggests that fundamental particles are not point-like but rather tiny, vibrating strings. String theory combines elements of quantum mechanics and general relativity and has the potential to explain various phenomena in physics. However, it is still a subject of active research, and its definitive validation as a theory of everything is yet to be achieved.
Additionally, other approaches such as loop quantum gravity and causal dynamical triangulation propose alternative frameworks for unifying gravity with other fundamental forces, without explicitly relying on quantum field theory.
In summary, while quantum field theories have played a significant role in our understanding of the fundamental particles and their interactions, not all proposed theories of everything are necessarily quantum field theories. The quest for a comprehensive theory of everything is an ongoing pursuit in theoretical physics, and various approaches are being explored.