Your argument relies on two strong assumption, "everything private economy is good", and "everything government is bad". Unless you add strong reasoning behind it such blanket arguments I default to scepticism.
I'm sure it will not fail right away, and there will be a sustained period of benefit. But I don't think it's worth the longer-term risk.
Know of any?
Any system of government that relies on a successive chain of responsible people in power is doomed to fail more quickly than anyone thinks. This is why the American idea of "ambition must be made to counteract ambition" is so powerful.
The assumption that CBDC is a good idea because the government is always benevolent and does what's best for the people is incorrect, as demonstrated by the horrible financial mismanagement in the recent 20 years.