When you create an integer-attribute in an entity you could use it to add the numbers. Then create an On Change microflow that is triggered hitting the button. In the microflow you are able to change the object in which you add 1 to the integer. Then you could change it to a string (another attribute) and place "item-" in front of it.
Based on the above method u should increment your integer value…. Here I create one attribute called Value with default value 1.. While clicking button it call this microflow. Here also simple things just create object with these attribute and change object accordingly like Value+1..