Carbon dioxide is a natural yeast by-product, the only way to stop it, is to kill the yeast. Don't do that.
Yes, CO2 will slightly alter the flavor profile of the finished product. However, if you don't like your kombucha carbonated, all you have to do is degas it by gently shaking it in a container before drinking it. This will make your KT "still". Think about how flat soda tastes compared to carbonated soda. It is one purpose of the secondary fermentation process that we capture this gas and force it back into solution to produce the desired carbonated effect.
My advice, stop messing with it. From your images, your batch looks perfect. Personally, I like my scobys to have the bubbles trapped in them. Makes it a whole lot easier to re-float it after the brew is harvested.