"When a state issues nominal bonds (bonds that pay in euros), the real value of interest payments varies with inflation, creating risk for investors. So they require a higher interest rate to compensate for the risk."
I doubt that. As long as the (expected) yield is higher than the deposit rate, investors will be happy to buy bonds with their reserves. Also, there is a fallacy of composition involved, as inflation erodes the purchasing power of all nominal returns. (99.9 percent of all assets are not "inflation-protected", I would guess.)