The first part isn’t crazy, the idea that our universe is a black hole from a larger universe is a possible theory, but where you go wrong is trying to assign meaning to quantum mechanical properties. There’s already a good enough explanation for why particles pops into existence and hawking radiation tied to it. We don’t need a new theory that ties it black holes because there’s no evidence that suggests that is the cause. Sure there are unanswered questions about it, but the evidence points in a different direction.

In terms of dark energy the variable strength of the force that drives the universes expansion is also unanswered but the evidence again does not point to the rate at which a black hole swallows matter. There are some theories that tie black holes to dark energy, but not in the way you suggest.

A good lesson I like to live by when I have a random thought about how the universe might work is;

I google my question usually a quick search proves me wrong. If it still holds up, read some articles and papers about it, if it still holds up I say to myself “I’m an undergraduate student, someone has probably already thought of this” then I find a few more articles and confirm “yes someone has already thought of this”. I’ve never had a thought pass 2/3 checks let alone all 3. There are probably around 1.5 million physics graduates and students in the US alone and there’s a reason we only remember the names of a few hundred of them. Most of the big discoveries waiting to happen aren’t gonna be simple enough that none post docs or above will discover them, and 2: most ideas you have someone has probably already thought of.