Well, on the one hand, we kind of are only as important as ants on an ant hill in the context of the universe. But we're told explicitly that despite that, God actually cares deeply. So from our perspective, we want to imagine ourselves as super important, but we were supposedly created by a being that lives outside of time and space as we know it. So from that humbling perspective, I'm relieved it's not far, far worse for us. Worst case is the atheistic view that we are a random species on a random planet, flinging through space. Best case is were are a created species and the creator cares deeply about our situation.
As far as the consequences - again, just guessing, but before He was this invested and before we made this super interesting and complex planet full of all kinds of diverse good and evil - I think, yeah! If humans did as they were told in the garden then supposedly we'd live forever, without evil, without disease, etc. But when they made that "choice", I imagine God could've said "Hmm.. let's see how this plays out". He could've equally wiped them out and started again - or maybe He did do that several times, first?!
As far as being an experiment - I don't necessarily think so. I think that in His reality, this could be a way to CREATE new friends and family that subscribe to your belief system. If this were a mere game, then I think we'd be in much, much, much worse shape in terms cruelty and tragedy. I know sometimes things can "feel" terrible, but objectively, they kind of aren't. There is an enormous amount of good and positive things in this world - which is an indication to me that He's still invested.
And honestly, this is pretty much as far as I go with the guesswork. In the end, I'm just trying to make it through this life - which in the meantime DOES have a lot of cruelty, tragedy, and struggle. So, I'm just looking for a way through. When I look at Christianity, I approach like I do many things: what are the facts, logic, and personal side of this. For example:
Where I am now is I've seen enough with my own eyes to "know" this is something. So, I take Him at his word and believe what He says to be true. There is an enormous circumstantial, but undeniable case that this is true.
As far as getting the rest of the backstory, and arguing the ethics of this - I concede that I don't know the rest of the context of this human project and I quite literally may not even have the physical brain capacity to understand the scope of this project. We're talking about someone who lives outside of space and time, invented the universe, invented physics, etc. Luckily, I don't need to. I already have my hands full every day trying to learn more, and trying to become a better person. Or Matthew 6:34 "Therefore do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own."
In the end, I totally get what you're saying, and that you want a concrete, air-tight story. But at the size of this earth and timescale of millions of years, it's messy, but elegant and nuanced. We're told a lot about what His nature is, what our nature is, and what we should be doing. But if needing to know the whole, inter-dimensional story is a showstopper for you, intellectually, then that's probably where this pursuit stops because it's literally unknowable. I hope some of that helps.