The amount of debt we are taking on is certainly relevant, it has strong effects on interest rates and inflation.

Using those metrics, interest rates, and inflation, to figure out what's going on, makes sense. Using nominal national debt doesn't.

And worrying about the "debt ceiling" is a complete and total scam. It's utterly meaningless and the only reason it exists is because people thought it would be a clever political tactic to use in cutting social insurance.