This is known as a "hidden variable theory". People will tell you that a local (things can only affect their immediate surroundings) version of the theory is impossible because it would be a violation of Bell's inequality, but there is a loophole that requires accepting the idea of "superdeterminism". This is the idea that where what measurement a scientist chooses to measure is predetermined and correlated with what the particle being measured is going to do.
So if a particle lands on a screen according to distribution p when going through a double slit, but with distribution p' when one of the slits is measured at, conventional QM says that the measurement "collapses the wave function". But a superdeterministic local hidden variable theory would imply that the choice of whether to measure at the slit or not was already set in stone at the same time that the particle "decided" which path to take to land on the screen, more or less.
Quantum physics makes predictions that suggest this isn't so. You can design experiments (e.g. A Bell inequality test) in which quantum physics predicts correlations that go beyond what would be possible with some hidden local information attached to the entangled particles that we just don't know about. Experiments don't prove theories to be correct. That's not how science works. However, experimental tests of Bell inequalities have pretty conclusively shown that local hidden variable theories are inadequate to explain what's going on.
Yes, it appears what Einstein called "spooky action at a distance" seems to propagate close to instantly. It's important to appreciate that you can't transmit information this way though. We can only make sense of the quantum correlations after communicating other information at classical speeds. Sometimes you see quantum entanglement devices allowing FTL communication in sci-fi, but that's pure horse hockey.
That all being said, I don't understand quantum physics either.
The important distinction in this case is about FTL existing but not being able to exploit it for FTL communication.
In reality the entangled particle will interact with something almost instantly thus collapsing it. The cat is actually dead or alive from the perspective of the microscopic things in the box. A world never witnessed or measured by a being doesn't collapse it's entire history of interactions of every subatomic particle, atom, molecule and emergent property from the start of the universe to 'now' instantaneously upon being viewed. The photons from that world have been hitting earth continuously since earth existed after all.
The new thing you're mentioning is a common observation about observers: if there are two cats in the box, should they be |dead dead> + |alive alive> or is one measuring the other and they've collapsed to a classical state? This depends on a person being outside the box; the scenario is called Wigner's friend. It's been used to show many other unintuitive aspects of quantum physics.