You will probably not be happy with the additional weight.
It's not all about tow capacity, or safety. First and foremost it's about your comfort. That goes against what most people will tell you. They will try to brow beat you and tell you that you will be murdering busloads of orphans and nuns by going one pound over the ratings, but the reality is you will HATE driving the rig long before you become a public menace.
Starting with a 5500lb trailer you are probably running around 6500lbs fully loaded. That's a respectable load for an F150/1500 type pickup truck. Your proposed new trailer will exceed 9000lbs loaded, because you will NOT be putting the "exact same" stuff in it. It has bigger water tanks. It has more storage space. You will be putting more in it.
Ignoring all other factors, towing anywhere near the maximum rating with an F150/1500 style pickup truck is simply not enjoyable. It's not something you want to do over long distances on a regular basis.