I stumbled over that switch too but as you say it does solve only half the problem when using Sorting (which I do).
So I was thinking about a switch "Extract and Post-Process in incomplete folder (slow with multiple hdds)" that allows to choose this approach deliberately
Simple one: UNRAR to temp folder, THEN move
Re: Simple one: UNRAR to temp folder, THEN move
I would not use this option. I don't unrar to the same location because it thrashes my HD. I set the complete folder to a separate local disk to avoid the head seeking that results from massive simultaneous reads and writes to the same disk.