A heuristic sketch how it could fit all together with time

On a scientific meta-level, it is discussed how an overall understanding of the physical universe can be built on the basis of well-proven theories and recent experiments and observations. In the light of almost a century of struggle to make (common) sense of Quantum Mechanics and to reconcile it with General Relativity, it is proposed to (for some time) forget about quantizing gravity or striving for one Theory of Everything or 'Weltformel', which would describe the whole of reality seamlessly without any joints or suture marks. Instead of one single monolithic formalism, a three-legged compound approach is argued for. Quantum Mechanics, Relativity and Thermodynamics are proposed as the main pillars of reality, each with its well-defined realm, specific features, and clearly marked interfaces between the three of them. Not only classical reality, which is rather directly accessible to us, is then comprehensively modelled by their encompassing combination. Quantum phenomena are understood as undoubtedly lying at the bottom of classical physics and at the same time, they become 'fully real' only when embedded in classical frames between preparation and measurement in time. It is then where thermodynamics steps in and provides the mediating glue as it does at interfaces towards gravity. The aim of this short contribution is not to deliver novel quantitative results but rather to propose a comprehensive research program and to coarsely lay out a very roughly coherent self-referential sketch starting from the beginning of the one universe, which we inhabit.