It's deceptive to conflate the Fed's response to the 2008 financial crisis with normal non-crisis operations.

It's true that the Fed purchased a lot of securities in response to the crisis.

You can see their balance sheet ballooning from $0.9T to $4.5T here --> https://imgur.com/a/PGthKNj

When the Fed buys securities, they essentially create new money out of thin air. So that's $3.6T of new money.

But that program ended four years ago. Since then the Fed's balance sheet has been gradually shrinking.

Since the program ended, the Fed has sold $0.4T of those securities.

Just like the Fed creates new money when they buy securities, they destroy money when they sell securities.

So for the last four years, the Fed has been destroying money, not creating it.

This has nothing to do with the national debt, or the government selling bonds to finance the budget deficit.

With the exception of the Fed's crisis response (which ended four years ago), the bonds that fund the national debt are held by the general public and as foreign reserves by nations around the world -- not by the Fed creating money.