I had a similar issue with my 2020 supersix during the first weeks. One night I cleaned the bike while it was hanging vertically and decided to loosen the clamp and torque it again. While doing that I heard a click, like something adjusting it's position and ever since the creak is gone. Sounds strange but it could be that the clamp is not positioning correctly in a horizontal position.
Just hang the bike vertically, loosen the bolt and torque it again. Maybe it also helps for you guys...