Hello,
Here, I add one condition which check for if there is any null value in "ZIP/Postal Code" or "Street" field. If yes then update in excel.

Note: ZIP/Postal code is a multi select column. And Contain null value.
I also try with empty function but as it return true or false it won't work. also try space value. Flow always continue with no, even though the field contains null value[""]. Is there any solution to get condition result yes or skip null function with any other function.