What more can central banks do if the economic situation worsens?

What could the Federal Reserve and the ECB do if the economic situation in 2021 turns out to be much worse than expected today? Such a worsening of the economic situation could be caused by a prolongation of the COVID pandemic and by a deterioration in companies’ situations. How could the two central banks then respond? Cutting key interest rates further or buying more bonds? It is not clear whether this would be effective, as a further fall in short-term and long-term interest rates could become counterproductive as the banks’ situation would deteriorate (the interest rate would fall below the “reversal interest rate”); Buying equities? At the current level of share prices, and given the risk of moral hazard, this seems to be ruled out in the United States and the euro zone, even though the Bank of Japan and the Swiss National Bank are buying equities; Announcing that the current policy will be continued over a longer period of time seems to be the most likely solution for the Federal Reserve and the ECB .