Understanding observation and why Schrödinger's cat is dead?

Understanding observation. What is there that really matters when we consider the impact observation has in quantum phenomena and not only? Interactions. I read in 'What is reality' website, in 'Quantum decoherence' chapter

"What happens in the real world is that a particle is not perfectly isolated: a particle inevitably interacts with the environment. These interactions have the effect of the particle "being observed" by the environment"

... particles, quantum entities, in isolation? And while, or more likely, if in isolation, exist in a superposition of states? However, isolation is a situation hard to come by. Particles everywhere, interactions ensue. Interactions which have the effect of particles 'being observed'. Observation being one way to trigger interactions. And as in the example cited

"when you take the temperature of an object using a thermometer, you have to remove a very small sample of heat from the object."

even by seeing an object we take in, no matter how imperceptible, an amount of the electromagnetic energy inherent in an object, carried by the photons that hit our retina. And, as it is further mentioned

"The measuring device has altered the object-"

The measuring device, our retina, alters the object? The observing human individual, the measuring device, measurement a form of interaction, interactions ongoing since the birth of the universe or even earlier, eliminating any anthropic principle notions? The universe does not need us?

And even though in the macroscopic world that amount, amounts to nothing, it is not the case for the microscopic, the quantum world. Each photon that enters our retina hits first the object. Trillions or zillions of particles in the object are hit. Zillions of electrons in the outer orbits of the object's surface atoms excited by the incoming photons, jumped to higher orbits. Their superposition of states decoheres. Zillions of decohered electrons combine into the object? The object altered, collectively? Collective decoherence?

But the object was already decohered, being a part of a massively populated, by objects, environment. Where interactions are constant. And have being going on for eons. So the world is there. A mass of objects, (decohered? Yes.) of every size possible, living or non-living where observation does little, in its day-to-day rigmarole. It is already decohered, it does not alter further.

Where observation plays a role is where state superposition still exists, in remote and safe isolation, as it is in the deep recesses of atoms, where Planck scales considered, quantum entities are thousands of miles away from other particles or where it is artificially induced, in physics lab as it is mentioned

"... recent experiments have managed to delay decoherence by decoupling quantum particles from their environment."

where decoupling quantum particles from their environment effectively isolates them. But not in a hermetically sealed box, where the poor Schrödinger's cat is dead, long before any benevolent soul opens the hatch. The interactions already established, the decohered poison kills the cat instantly and observation or not, amounts to nothing.