In quantum mechanics, we are further from the theory of everything than climate modellers are of future climate.
It's wrong. The equations of quantum mechanics work perfectly, in their field.
Relativity works perfectly, in its own.
Both can predict the outcomes of phenomena, and unlike climatology, by quantifying them correctly.
Research focuses on finding the bridge between QM and general relativity, because QM is not compatible with GR. The "theory of everything" is just a fancy name, especially for the general public, not a science.
No physicist claims to have this unifying theory, only hypotheses, and even then, limited. And even less, physicists predict future phenomena based on their assumptions, except to verify them. Unlike climatologists, when the measurements don't match the theory, they reject it and move on to another, they know they don't have the science yet.
We are far from the digital toys of climatologists! Moreover, it is generally physicists who point out their blunders, particularly in thermodynamics and statistical processing, a shame given that these are critical points in climatology.
In climatology, the complexity of the phenomena involved, the enormous number of parameters, of which we are far from knowing precisely the mathematical relationships that link them, some of which are not known or quantified with sufficient precision, and which are critical because the evolutions are chaotic and diverge easily for a tad difference from the starting values, produce the results that we see: forecasts that do not work. There is no climate science yet, only a vague outline.