New 2025 Ram 1500 Floor/Driveline vibration

[Angineer]

Hey everyone, I have a 2025 Ram 1500 with the Hurricane SO engine that has a very annoying high-speed vibration coming from the floorboard at highway speeds (73 mph and above). I’ve been trying to diagnose it since the day after I bought the truck brand new a few months ago. The dealer initially blamed the tires or balancing, but after road force balancing, rotating, and even replacing all four tires, there was no improvement. After digging deeper and attempting to diagnose it myself, I found a potential alignment issue in the truck’s driveline. By measuring the pinion gear, transfer case output shaft, and rear driveshaft angles, I discovered that the working U-joint angle is approximately 4.7–4.9 degrees, and the transfer case output flange is not parallel with the rear differential flange. My understanding is that the rear suspension on our trucks is not adjustable, so how can this be corrected? Has anyone experienced a similar issue or dealt with this kind of problem? Could this misalignment be the cause of the vibration?