You might get an infrared gun to periodically check the drum temps. If one side is significantly hotter than the other, there's a problem. Bearings are made over in China and can fail in some cases. US-made replacement bearings are a good substitute. TTs have been known to come from the manufacturer with too little or too much grease. Too little would lead to overheating and too much can cause blown seals. If you happened to have blown seals, it's possible there could be grease on the brake surfaces. Had that happen on our first TT and the dealer had to completely redo the brakes & seals.
I would pull the wheels and drums off and inspect the brakes and also do a bearing inspection along with new grease and seals. You want the P3 controller. It may need to be dialed down. There is an adjustment procedure which will be in the manual. Gearing down and using less braking should help a lot.
Do you add much in the rear seat or trunk of the SUV? It's rear springs are going to be softer being primarily a passenger vehicle and the trailer's nose could tilt down farther. Too much down could adversely affect braking in the SUV and potentially be unsafe.
If the problem persists and nothing seems to help, perhaps you could upgrade to larger dia. brakes but that could get costly if it means you need to replace the wheels too.