It's not entirely clear based on your description, but if you want to achieve a dropdown list that automatically adjusts while you are typing an entry (in the same field) you can use the AutocompleteForMendix widget as a possible solution.
Another way to do this is to use Constrained By in the Selectable objects tab of the Reference selector. This will dynamically update the list of selectable objects based on other references the user has made a selection for.
In the Reference Selector there is option for Selectable objects, there you can call a microflow and retrieve the list based on the SMID and return the list.
Add a On change microflow in your SMID text box and refresh your Data view Entity, which will retrigger the Selectable object Microflow and fetch the values.