Thanks for this, it's cool to see some others coming to some similar realisations as I have, studying what I call the great energy problem seven years and counting, since coming across it as a long practicing Systems Engineer, working at that time on PhD candidate research.
But we are a little different in our conclusions.
What it looks to me like you are doing, is starting out with a kind of faith, even a determination, that what you say will be.
This is something I notice with all degrowthers, maybe because you haven't been able to do enough mathematical modelling of the system, to prove or disprove your overshoot / degrowth theories one way or another, understandable because those kinds of skills require a lifetime of system modeling exoerience, you have to make up for lack of that skill with faith, based on your own life experiences.
I notice also you mention in many places your certainty we will be fighting.
So you expect a fight, with your fellow humans, over dwindling resources.
I put it to you this won't work, this is the thing unsustainable, the fight is what is unsustainable, and that is what you appear to be willing on, in your way.
We already lost, if we can't stop the fighting, because the energy being lost and wasted by the stupid, insane fighting, dwarfs all others.
It looks like you haven't included the energy of the fight in your evaluations.
It starts with the energy of competing, the energy of competition, the energy of profit.
Am I wrong about that?
Have you done any such modeling?
Do you know anyone that has?
Would you want to know anyone that has?