The TBT-UDM is a Thunderbolt 4 docking station based on the Intel Goshen Ridge chipset. The display output capabilities of the TBT-UDM are ultimately determined by the display output capabilities of the host system.

Apple M-Series MacBooks:

When the TBT-UDM is connected to a M4 MacBook, M3 Pro/Max CPU MacBook, M2 Pro/Max CPU MacBook, or M1 Pro/Max CPU MacBook, up to 2x external displays are supported. 

Base model (non-Pro/Max CPU's) M1 and M2 MacBooks can only support a single external display.

Base model M3 MacBooks can support up to 2x displays only when the lid is closed. Otherwise it will support a single external display.

The TBT-UDM has 2 built-in HDMI video output ports, and one downstream Thunderbolt port.

A USB-C cable or video adapter can be connected to the downstream Thunderbolt 4 port to connect a display.

The video outputs via the TBT-UDM are provided on a ‘first come, first served’ basis. This means that if a display is connected to the downstream Thunderbolt 4 port on the dock, you can connect one more display to one of the HDMI ports.

If both HDMI ports are occupied, the downstream Thunderbolt 4 port will not be able to output to a display. However it will still function as a Thunderbolt 4 port in other aspects