> taking toxic loan assets of banks balance sheet and absorbing it onto the fed balance sheet
This is not what happened. (The Fed never bought the toxic assets. It bought Treasuries and super-safe nontraditional assets off owners of toxic assets so they had the liquidity to resolve themselves. But the toxic stuff ended up in other places.)
> Central Banks give banks cash in return for garbage mortgages
There are zero mortgages on the Fed’s balance sheet. There has never been a mortgage on its balance sheet. If you think the Fed bought whole mortgages off banks for keepsies, or lost a single cent on its bailouts, you’ve missed something.