Am hoping to receive assistance from anyone familiar with the parking options at the Stuttgart Airport. Looking for the most convenient and closest option, preferably with direct access to the departure terminal. The airport website has a curious description in which one comfort option (P14) is half the walking distance of P6 but 3€ less.

Thank you in advance...bdj

There is only one parking option (P7) with (relatively) direct access to the departure terminals, but that is only for short time parking unless you would like to spend a lot of money. And it's in the open air.
P6 and P14 are only a short walking distance from the terminals (at least as far as Europeans are concerned). As Stuttgart is a relatively small airport there are hardly any very long distances to walk.