Printing large amounts of money out of thin air is a great way to turn a valuable currency into worthless Monopoly® money via inflation. That is basic economics. There are lots of examples for that in history.
Inflation is not a guarantee, that depends on the actual economy. Japan is massively in deficit and yet is seeing deflation.
Beeing deficit doesn’t have to mean that they print money, they can be deficit by taking higher and higher loans. Which comes with it’s own problems.