What happens to the excess demand for risk-free bonds when fiscal deficits are monetised?

The world is characterised by excess demand for risk-free bonds (government bonds issued by "safe" OECD countries), which explains the fall in the yields on these bonds and the rise in risk premia on risky assets. It might have been thought that the COVID crisis would have corrected the shortfall in supply of these risk-free bonds, but since the new bonds have been monetised , this is not the case. The question that then arises is: what will be the effect of the increased holding of money on demand for risk-free bonds: will money be substitutable for risk-free bonds or, on the contrary, will part of the additional money held be invested in risk-free bonds? In the first case, the excess demand for risk-free bonds will be corrected, in the second case it will be exacerbated.