Given the complexity in setup and operation, I decided to talk more about the software as you are effectively forced to use Lian Li's L-Connect3 software to do anything useful with these fans.

It could just be potentially buggy firmware on the controller preventing external controllers from working since I don't see a reason why this hub doesn't simply function as one anyway.

I initially had issues getting the fan motors to turn until I figured this out, as I was going to use my own fan controller as per usual to map the PWM/RPM curves the poorly written user guides don't help much since they omit the PWM fan header part entirely. Using the motherboard ports ensures the USB connection sees them as expected, with the hub having software control that is only looking for them. Then comes the part where up to five connectors from the hub-two SATA power connections, one internal 9-pin USB, and a 4-pin PWM-go to an available fan header on your motherboard and a 3-pin 5 V ARGB LED connector goes to your motherboard's onboard LED header. As such, the others are available for other fans, or compatible devices. In this case, the power module cable is attached to a 7-pin port on the hub. The back of the hub controller has a rectangular recess and comes with double-sided tape to stick it to the back of the motherboard tray in your case to hide the cable mess. It made me wonder why modular keyboards haven't gotten this part right yet! But keyboards don't have to worry about a multitude of connected cables, and a single cable from the fans leads to the UNI Hub itself. Even lifting the ensemble of three fans on a fan corner felt natural and led to no play between individual fans. Connecting the individual fans was the easy bit, and I was very impressed by how solid the connections were.

Lian li fans controller