You can Create a Non-Persistable Object A and create an Attribute for Count and inside your Ds Microflow after you have calculated the Count create the Object A and set the Count value to the Attribute in the Entity A and return the object A. In the Data view you pass the count Attribute and display it.
For your Reference:
Hope it Helps !!
Instead of returning the number from the microflow, return the object from the microflow which can then be used as a source for your dataview. The error should go away with this.
To show the count use the attribute in the label which would already be set in your object.
Hope this helps. Good luck!