You can't. You've been answering your own question.
There have to be various other ways to improve things like muscle synthesis; improve satellite cell functioning; increase nervous system and muscle recovery; and even increase size too.
Increase compared to what? You state no baseline for comparison.
Obviously besides just working out and "hoping." I'm talking about "natural enhancements."
Define "natural". Heck, define "enchancements". We're not replacing our weak limbs with bionic limbs on a whim just yet.
What else is there? What's the real holy grail that can (almost) compare to high doses of AAS/PEDs?
This isn't a secret we're keeping to ourselves. If we had the knowledge to gain equal progress WITHOUT anabolic steroids, why would people still be using anabolic steroids?
As long as it isn't AAS/PEDs. Good sleep never made me wake up looking like Phil Heath; neither did a 20,000 calorie surplus, 900g of protein, zero stress, or years of training. Something's gotta give.
No, nothing's gotta give. A 20k kcal surplus is going to kill you. 900g of protein is going to give you gastric distress. Zero stress is going to be impossible, especially with the aforementioned diet. Years of training is what we're doing. That, and a slightly more reasonable approach to dieting and rest than what you said.
How can we create true enhanced natties, without the steroids, growth hormones, insulin, etc.?
Now you're just throwing out buzzwords to see what sticks. Like I said, if bodybuilders didn't need the AAD's, why would they still be using the AAD's?
Remember, before this garbage existed we still played sports professionally & adored great bodies.
Yes, and the bodybuilders of yesteryear looked pretty damn different from what they do now.
Case in point; here's Mr. Olympia 40 years ago, vs. today.
Look, here's the answer to the question you're afraid to ask.
How can I look like a bodybuilder without using the same supplements as they use?
You can't. They use these supplements to break the barriers that the human body imposes on itself. Through decades of research, we have come up with the best way to do so, and the bodybuilders you see compete for the title of Mr. Olympia, are the result of this research.
If you want to look like they do, do what they do.