2025 HARLEY-DAVIDSON FLHX Structurebody Problems

This motorcycle is unstable at highway speeds. I believe the aerodynamics of the fairing and the front fender are to blame. It is not an issue when I ride the bike with a passenger, thus more total weight resolves the issue. I am 160 lbs. and when I ride solo and get around semis, or have a headwind, the front end begins to shake side to side at around 70mph, depending on the wind, oscillation begins and I need to pull over before the bike goes into a speed wobble (tank slapper). I've had the bike back to the dealership multiple times and they say there is no issue. They suggested upgrading the suspension, which I did and that has not resolved the issue nor is that money refundable. They have test ridden but it was a 190 lbs technician. Again, this doesn't happen with heavier riders or with a...