[dredmorbius]

There are several subs I'm aware of which do seem to garner expert-level moderation.

The Asks -- Science, Historians, possibly Economists (I'm trying to decide there -- the mods talk expertise, though quality IMO lags). Several of the Fitness subs are quite good. Various technical subs attract high-quality contributors, and the CSS support sub (specifically for styling old-style Reddit custom stylesheets) is simply superb. I've dug into energy topics, and though there's a bit of BS flung about, there's also quality expertise.

Posting online actually is a form of shingle-hanging and getting a sense of issues people are facing in the real world. There's value to that.