Do you have to much weight in the trailer up front or in the rear? Like Rookie said you shouldn't have wag even without WD bars and anti sway. Not sure your trailer weight but just guessing I would say your TV should be able to handle the load so I would look at how the trailer is loaded. Biggest thing on fifth's is stuffing that huge front pass through full of heavy stuff.
I see yours has the rear kitchen which can contribute to having more weight behind the axles then in front which causes wag. Maybe you don't have enough stuff in your front pass through. Good starting point is to carry 60% of your weight in front of the trailer axles then adjust from there. A simple fix could be you are not running with your fresh water tanks full and if they are in front of the axle this would probably give you the weight you need to stop the wag as trailers are designed to tow with full tanks.