What a great and honest reflection, Chris. I very often look back at my past and think 'how naive, foolish, and ignorant I was then!' which, these days, is always followed by the thought 'how naive, foolish, and ignorant am I now?'
We're all just blundering around most of the time, successfully or not, self-questioning or not depending on various perspectives (though it's nice if one can say that one has become, if not wiser, then at least more questioning, over time).
I'll put your article alongside the Marv Weisbord reflective piece and the podcasts Amiel Handelsman did with Peter Block and Ed Schein, linked here - https://stream.syscoi.com/2019/12/24/seasonal-thoughts-from-the-toolshed/
I guess this is summed up as 'impostor syndrome can be important and valuable, however expert and experienced you are'!