Really good write up... I think the most annoying thing about "corporate agile" as you put it (which I've unfortunately worked with a few times), is that it adds unnecessary layers of bureaucracy which doesn't seem to contribute at all to the final goal. I've even seen it as a way to prevent work from getting done, by saying things like "we can't do that many story points in a sprint". Then that work ultimately expands to take up the whole sprint, even if it shouldn't (as per Parkinson's principle).
Nothing drains my soul more than a discussion on whether a story should be a task or epic in Jira, or getting engineers to go away and spend 2 hours by themselves assigning story points.