I’d say he has become intimately aware of how it works - your list of his “faults” seem to revolve around him not being a politician so he trusted the wrong folks - that can be an asset after lessons learned.
Just my opinion.
Agreed - but I don't see any signs that he has actually learned literally any lessons. He doesn't seem to have learned any of the technical/legal stuff himself, nor has he surrounded himself with better people. If anything, the people around him are even worse now.
You don't have to be a politician if 1) you have trusted people who share your vision, and they understand how the system works, 2) you are a high-detail guy who digs into this stuff and learns quickly, or perhaps 3) you aren't a politician but have otherwise been immersed in law/governance and so understand the legal/governmental systems.
Kushner seemed to understand enough of how things worked to have been useful, but he really didn't share Trump's vision on a lot of issues. And he's gone anyway.
Reagan is the classic non-politician who succeeded, but he had multiple consiglieres in James Baker, Michael Deaver, and Ed Meese. Meese and Baker were both lawyers who understood the Constitution, regulatory system, etc..
Trump has none of that, and I'm not sure who other than himself can be blamed for the people with whom he chooses to surround himself.