Not necessarily. You can apply all types of forms of high carbononeous materials and mulches on top of the ground (i.e. sawdust, pine needles, wood chips, paper, cardborad, etc.), and it doesn't really have to alter your lower topsoil soil pH nor rob your topsoil from available nitrogen.
Keep in mind that good sustainable soil building and composting is based on balance, soil biology, soil chemistry, and lots of patience! Feed the soil!
If you apply a good rich protein fertilizer like grain meals or blood meal or fish products underneath the carboneous mulches or layers, you will never disturb the carbon-nitrogen ratio balance. There will be plenty of carbs and proteins for the beneficial soil microbes to digest into available nutrients for your plants, and improve the texture and conditioning of the topsoil.
Also if your native topsoil is too acidic or too alkaline, applying the correct amounts of either a little lime or sulfur underneath the carboneous mulches, is also a great idea. With the balance of protein fertilizers and extra calcium or sulfur underneath, the soil microbes with naturally regulate and balance the soil pH. Over time heavy composted mature organic soil always has a near neutral soil pH anyway. The soil microbes and earthworms take care of all that over time.
The entire Kingdom of God can be totally explained as an Organic Garden (Mark 4:26)