To some extent I think Louie set the precedent there, as CK was given complete creative control. Comedians were asking for "the Louis deal". Glover (and Ansari) seemed to get it, and both had the sense to hire other talented people. Louie (the show) suffers from its self-indulgence to the point it can't be rated that highly, where Atlanta maybe mostly avoids that fate.
I would say the marvel tv series so far have been pretty solid. Even if you don’t like them because you have an allergic reaction to marvel, their execution has been really good.
If we must talk of THE BEST, then season 1 of American gods on StarZ was the best season of television I’ve ever seen. Mostly all written by Bryan fuller and Michael Greene. Not entirely. How do we weigh this? Hard to say, but man did that show crash and burn when they left.
I saw the first season of American Gods on Starz as well. It did not motivate me to watch the second season. That same year, though, we had The Good Place (showrunner), Better Call Saul (showrunner), The Deuce (showrunner), The Leftovers (showrunner), Maisel (showrunner), and Legion (showrunner). I think the model acquits itself nicely.
The result was that each episode often had a very distinct style, which matched well to the underlying theme of schizophrenia.
Edit: I guess you're referring to the various recent miniseries Marvel has been doing? It's never been uncommon in miniseries, for fairly obvious reasons.
I recently noted the same while watching Severance. Almost all of the episodes, barring one or two, were directed by Ben Stiller. I found it one of the best (first) series ever.
As for OP's point, with the series' budget so high, a gun-for-hire TV director might not be accoustemed to the staggering budget they have to manage.