Make datacard default stick with combobox

[powerapps890]

For one of my datacards(datacard16) this is what I have in my default ComboBox2_2.Selected.Value & ComboBox2_3.Selected.Value & If(!IsBlank(DataCardValue15), DataCardValue15.Text). The problem is the combobox value disappears after the form is submitted. How can I make the combobox value stick as the default if it is selected. I also want the other combobox value or datacard15 to override it if it is selected. If I were to go back in a submitted form and hit submit again without choosing a selection again there would be nothing in my default. Basically I need each of these values to override each other and stick in datacard16. Is there any way to do this?