Apps, Data Service entity and List (of) variable

I have a multi select dropdown which I am able to populate with an entity field, what I am unable to get to work is this:
I have a List variable where I store the defaultSelected items triggered by which radio button selection is made. I want to populate this variable with the results of a filtered query on my entity, it doesnt seem to be working but I know the filter itself is working because I am able to populate a display table using the same query.

@corinna.robertson ,

Can you share some screen shot ?

Thanks,
AK

Is this what you want to see?
What I initially did is create a variable and set it to that filter then put the variable as the default selected value but that also did not work, I suspect I need to return only one column with my filter but not sure if thats possible here