In every other windows application I am aware of Combo Boxes allow selection from a dropdown OR text imput. PowerApps does not allow text input. It appears a "combo box" in PowerApps acts no different than a dropdown other than allowing list filtering based on typing (both can have multiple selection).
PLEASE update combo boxes for this.
For data entry forms this is a critical capability to limit key stoke errors while still allowing new response answers in a dynamic format.
Unless someone can point me at an alternate solution, the only way I can conceive to do this given the current options is to create a top screen with a drop down list and a text field for every single question. Then put the data entry form on screen two and rationalize between the two fields on screen 1 for that Card. I.e.: if user selects "NEW" from the Screen 1 Question 1 Dropdown list then Card = Screen1 Question 1 Text Input, else Card = Screen1 Question 1 Dropdown result. This type of programming could drive the logic so the form gets filled with the right data.
Ton of work for a control feature that exists for combo boxes outside of power apps today...