Heavier WD Bars Or Different Sway Control

You can't magically make the wind go away, the side pressure will still be the same regardless of what hitch you have. Yes, a firmer connection to the truck will lessen the feel but it might be better to just keep it as is and take the hint that maybe you should pull over and wait for better conditions.

What you describe is one of the reasons that folks on this forum often recommend a 3/4 or 1 ton truck, for trailers the size of yours, for more safety margin.