What is the proper way to insulate a cathedral ceiling in a dry climate? (Southern California)

I've got an exposed beam ceiling, but I need to close it up and insulate it to keep the heat out. (The previous owner removed the drop ceiling and just stained the rafters to finish them off... so no insulation... under or over the ceiling)

So far 3 general contractors and 2 companies that specialize in insulation (all with a large number of positive yelp reviews) have all said that R19 batt insulation between the rafters and then drywall/ gypsum board over that. This would make it an unvented setup. They have all said they've done this setup all over socal with no issues as far as condensation/ mold even though it's un vented.

But when I google how to properly do this for an unvented setup... they all say either spray foam then drywall or rigid foam then drywall or "flash and batt" with 1 inch spray foam then r19 batt.

They are all willing to do it the same way that I've researched, but they all insist to just save the money and do r19 and drywall over it and call it a day.

So what is the correct way for socal? And why are so many different reputable contractors wanting to do it the other way? Is our climate dry enough to just use the batt insulation and drywall over that?