Yes it is like a credit card. You have to make payments and it reduces your cash flow. The Federal Reserve prints money not the government. And payments aren’t made with printed money.
In modern fiat money, the money isn't printed. It's created by issuing bonds and then counting those bonds as an asset. The money is created when the bank loans out money based on those bond assets.
If you believe it needs to be ever paid back, it hasn't been paid back since 1914. It just grows ever larger.
The initial 1914 version pegged the fiat money to gold. Like all pegging systems, they eventually collapse catastrophically, and this one did in 1929.
I disagree with the theory that we can grow our debt forever without consequence. I never advocated pegging to anything.
Private banks create money through lending, correct. Lending is constrained by the supply of creditworthy customers. Money is not issued by decree by the Federal Reserve or the government.