Having two different fields symbolized to give four options in ArcGIS Online, Collector

I have a integer field for "agency", and a string field for Survey Status "SURV_STATU"

Each field has two options. I used this Arcade line to see the desired symbology in ArcGIS Online.

Concatenate([$feature.agency,$feature.SURV_STATU], ”)

Since I used Arcade to make that symbology change, the layer is not visible in Collector. Can anyone explain why, or show another way to symbolize the 4 outcomes of one layer?