Vibration from speed 85 – what else to do?

Dear Volvo-Bande, my fat guy is worried about me. For some time now, a speed-dependent vibration of the entire car appears from Tempo 85. In long-drawn left curves much stronger than when driving straight or in right curves. From 110 it is hard to feel, but probably only because the vibrations are then so fast…. Wheels are balanced again, rims have no impact. The usual suspects (coupling bars, carrying joints) are checked, brake discs and pads as well as lateral handlebars at the front (which had to be after 350 tkm anyway) are replaced. I would have now suspected the right drive shaft… Do you have any other starting points? Auxiliary frame suspension, rear wheel suspension/crossbars? Please have understanding if I can not react quickly to all the answers. Unfortunately, my job does not allow me to do so. Already thanks for your support.