Can monetary policies ensure fiscal solvency without causing other turmoil?

One of the interpretations of the highly expansionary monetary policies conducted nowadays in OECD countries is that they ensure countries’ fiscal solvency. The positive side of this choice made by central banks is that it prevents government bond crises. But is there n o negative side? Is it a pure "free lunch": do expansionary monetary policies prevent public finance crises without any associated cost? These policies are in reality dangerous: They may lead to a limitless expansion of the size of the central banks' balance sheets, leading to a risk of flight from money (economic agents get rid of money to buy real goods or assets, leading to either inflation or bubbles in the prices of these assets); They may encourage governments to not stabilise public debt ratios, which makes these policies irreversible; They make it possible to finance inefficient investments; They drive down risk premia on risky assets to an abnormal extent; They prevent central banks from reacting to shocks that would normally require them to hike their interest rates. So there is no "free lunch" associated with monetary policies that ensure fiscal solvency.