The spec sheet mentions 6 antennas and implies only 2 are directional:

(6) Embedded cellular antennas, including (2) high-gain for downlink: peak 9 dBi, 85°x85°

Typically these modems are 4x4 mimo so it must have some method for switching the 2 directional with 2 of the omnis in it based on which ones is needed.

https://techspecs.ui.com/unifi/integrations/u5g-max-outdoor?...