In a completely hypothetical scenario- if every morning another zero was added to the national debt would there be any downsides? All other variables remain the same, unemployment, GDP, etc, only the debt increase ten-fold.

Does debt not matter because we have experienced relative stability and growth for 70 years? If we had another depression (not the hyped great recession but true depression) or world war, would we be better off with less debt or does it truly not matter?