Question about Icy Box IB-DK2102-C - 11-Fach USB-C Dual Dock 60W PD

This dock only supports the connection of 2 external displays with windows. It says in the description

Hoi Benj - were you able to solve your problem? Apart from your dual screen problem, did all the other connections you used work? Thanks a lot, Stefan

Have you already tried to adjust various settings under "Apple+ (top left) -> System settings -> Monitors under the sub-item "Arrange"?