Question about i-tec USB 3.0 / USB-C / Thunderbolt 3 Dual 4K Dock

I recently bought this one but had to return it. I used it with a MBP 15" 2018 and a 4K monitor. After installing the drivers (Catalina) the interface and all its ports worked. However the 4K display did not support the resolution I need in 2x pixel density.