Dynamically assign color to map point based on dataset field value

I have a point layer in a map control that I want to dynamically assign the marker color, in this case I am using a PushPin.  I have attempted to do this using the MapLayer Point Properties and using an expression in the Fill Property and the Point Color Rule using an expression in the Point Rule Property:

When using the Color Rule I get an error

"The Palette expression for the map xxxx refers directly to the field xxx without specifying a dataset aggregate.  I am struggling on trying to dynamically assign the point color based on a dataset field.  Using the Point Properties Fill with an expression does nothing while the Point Color Rule raises and error.

Thank you in advance for any help

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