The ECB is already buying vast quantities of the bonds of those member states that would otherwise go insolvent in an instant. The way things are developing not many investors will be buying them.

I don't think the CBDC euro will have much impact in the short run. People will be keeping their money in their bank accounts and the banking system will not be done away with in the near future.

The ECB will go the Japanese way. Yield curve control to keep the long bond yields very low is a likely scenario.

https://www.ft.com/content/03e57b5f-e507-4e7c-a802-7545c8f557fb