Which interest rate should be used to discount the future earnings of euro-zone companies?

Currently, investors in euro -zone equities are visibly calculating the fundamental value of equities by using a higher long-term interest rate than the market rate to discount the future earnings of euro-zone companies. This explains the very high level of the equity risk premium on European equities, and it raises a key question in terms of analysing euro-zone equity valuation: what long-term interest rate should be use d to discount future earnings: The market interest rate, which is very low? A higher interest rate, with the idea that the ECB will normalise rates in the future? But this is not clear, as the ECB could keep rates very low; A higher interest rate, with the idea that a political crisis will return in the euro zone and sovereign risk premia will come on top of the interest rates in several countries? But will we not rather see relative fiscal soundness and low sovereign risk premia? This choice is crucial to determine whether euro-zone equities are expensive or cheap.