I do not know how the CBDC will be distributed, but most likely you will need a KYC verified wallet and it contains all the information about you. Therefore, USDT is still an attractive option for those who want not to provide their data or to send their money between countries, as it is expected that you will need a bank or a system such as SWIFT that can These CBDCs are used to transfer money between each other and basically determine the exchange rate, so USDT and stable cryptocurrencies will be with us for a while until the whole system is based on identity verification, and then they will disappear.
I think it won't be distributed just like that, like a relief goods that the governments are giving whenever there is a calamity, but picture out CBDC like a typical crypto. You will also need to pay in order to obtain them. But, maybe some employers will pay using it. I'm not only sure if they are also mineable. But if so, then this is another way of obtaining them. CBDC's are centralized because governments or the banks are behind them. So yeah, the possibility of KYC must be there. I think USDT has no difference to them.
If you will only say stable coins, maybe it is acceptable since there are also a decentralized type of it, like for example DAI. BTC is still the best option though. Most cryptos are decentralized. They are new way of paying or the future of money, so I don't think the last thing that you said is going to happen. But even if let say it is, I think that people are still free to choose whichever payment they want to use and some or most of them will still prefer the decentralized cryptos.