My trailer and truck are almost identical to yours. Get rid of the extra leaf springs. I assume you already have a wd hitch.
I added 4 good shocks, absolutely the first step. I then added some things called stable loads. They basically engage the overload springs. And the biggest improvement was a gen-y hitch coupler. I separates the truck and trailer by inserting a vertical pivot point. They are incredibly heavy but they work. A road near my house that I had to slow to 40 I can now run at 60. My neck no longer aches after driving 30 minutes.
It’s well worth the money and weight, IMO!