I did something like this in an app.
I use an extension so that the user can pick the Dimension that they want.
I load an inline table that contains the choices from the filter along with the actual field value that I need to get the data.
// Used to assign the correct field based on the selection made in filter on Patient Outcomes Sheet
Load * Inline [
'By EOC Destination','EOCDest'
In the table my dimension is defined as
$(='[' & only(Dim1) & ']')
The field in the filter extension is Display so that I can match it to the inline table.
Hope that helps as does what you want.