I think we are in close agreement with every point you make. A state exists only if it is measurable from the system’s ambient surroundings (or the universe’s cosmic or vacuum-state background). Its state properties are quantified by a perfect measurement process, but the state exists regardless of measurement, and measurement does not necessarily require a sentient being.

I argue that a system can also exist in an irreversible and random transition between measurable states, during which it is not reversibly observable, and it does not exist as a state. The transition is a response to a change in the system’s surroundings, but I don’t think we can say the system is interacting with its surroundings during transition, at least not as a state. A transition between states starts and ends at discrete points in irreversible thermodynamic time (measured by entropy production). These points are separated across a span of an observer’s reference time (time of relativity). Irreversible reference time and reversible mechanical time are continuous, but thermodynamic time is discontinuous. If one tried to continuously observe a system to record a continuous production of entropy, the Zeno effect states that there will be no irreversible production of entropy.