What the 14th Amendment appears to say, is that the public debt of the US must be paid, as a priority senior to all other obligations.
Put another way, the revenue of the US will be applied to the debt. Any money left over will go to legally-mandated appropriations like Social Security. Any money left over from that will be available to fund things like Defense, Education, etc.
Thank you for making that more understandable. I only wish Congress would do that instead of participating in the political corruption and squandering the future away.