Key take away:
When anticipating a refund, merely check the box that says, “Apply to next year’s return.” Then adjust withholding and/or quarterly tax payments accordingly.
That way, you aren’t waiting on the government, and you keep control.
If they don’t process your prior return, there’s no overpayment to apply. Let’s say your overpayment was a thousand or few thousand and you try to apply it. You’ll get billed for the overpayment that you wanted applied since they have never processed the prior return to know what you have available.