There is a truth that you need to accept that, whether we need CBDC or not, it will still be issued by the government and in the further future, it can even completely replace paper money. So as long as the government still controls us, it is mandatory for us to use fiat or CBDC in the future, we have no choice whether we want that to happen or not.
I don't see the usefulness of CBDC over fiat. The government is only using CBDC as the digital version of their money and therefore it won't replace fiat. Fiat is going nowhere because of its traditional role it does, there are things you need to buy and you don't need either btc or CBDC. Also, countries that are yet to have CBDC may prefer to rely on usdt or other stable coins instead.