As far as I know, CBDC is just a digital version of the fiat currency we all know. They are an evolution of what we have now.
That's been pretty much my understanding of what they are, but it's always puzzled me why a government would want to implement a national cryptocurrency for any reason other than financial surveillance. Right now, there might be a little bit of separation between banks and government, but it isn't much. If the government created a currency based on a blockchain that wasn't anonymous, it wouldn't matter if people still used it with the banking system because they'd be able to see all of your financial transactions from the present all the way back to whenever you started using the CBDC.
Physical currency is quickly becoming antiquated, which seems to bother no one but is disturbing to me. At present, the most anonymous form of money is cold, hard cash--as long as what you use it for isn't caught on some security camera and preserved for all eternity.
People's attitudes toward a lot of things bother me these days--from mask-wearing to giving up privacy to companies like Facebook-- and I see the world headed down a very dangerous path. Something like a CBDC might easily catch on in China, but man....I hope it never becomes a reality in the West.