The money supply is protected by the Fed, yes - that's kind of the point. The supply is adjusted to maintain the 2% inflation target. Generally in big financial crises, velocity of money drops so the supply is increased to offset it - and avoid a deflationary spiral.
It's pretty logical right? If the economy is imploding around you, your natural response is to save your money - out of fear - and not spend it. However, that has knock-on effects. If everyone starts saving, prices go down to tempt people to buy, which means less revenue for the business, which means salary cuts and layoffs, which means folks have less money to spend - and so on.
To avoid this situation, the Fed increases the money supply. This happened in COVID too. The fed IMO deserves a ton of credit for saving the American economy from a massive depression - twice so far since 2008.
By the way those bailouts earned a $15B profit for the government [1].
[1] https://en.wikipedia.org/wiki/Emergency_Economic_Stabilizati...