So the Alt Right is both accusing Biden of being a zionist, and antisemitic. He loves Blacks, and hates Blacks. I could go on and on, but we all know that the Alt Right is just accusing Biden of everything, and trying to see what sticks.
The Fed is not insolvent, and cannot become insolvent in any other way than the technical sense. These are not just words, they are basic facts that have very real meanings in our day to day life. The Fed only has debts denominated in US Dollars. It prints US Dollars. So therefore, it is impossible for it to run out of US Dollars.
Now if it did print trillions of dollars just to pay the debt, that would drive up inflation to insane levels. And that would be impossible for the government to hide from us. The government can hide many economic numbers to some extent, but cannot hide inflation.
Luckily, the Fed does not need to print dollars to pay off the debt. Lenders are willing to effectively pay the Fed to take money. The interest rate is below the inflation rate, so lenders are actually paying the US Government to take their money.
Why is this? Because it is cheaper to give the US Government money to store, than to store it anywhere else. The US Government is the only organization that can guarantee payment in US Dollars, so it is completely safe (other than Republicans trying to destroy America). If you put a million dollars in a vault, it will lose 2%/year due to inflation, and cost money for the vault and security. If you buy Treasurys, you get a 1.6% return, minus 2% inflation, so lose only 0.4%. And Treasurys are easily transferable electronically, where paper money is a pain in the neck to send anywhere.