People are already warned about CBDC I guess they all believe it's used for surveillance which people don't trust governments. Even if they allow CBDC to be used in buying BTC, the people will be more cautious because they get records of who owns BTC.
Brazil embracing BTC will make the country open for all because the impression is that people are free. BTC is here to stay, it doesn't choose whoever and whatever the owner may do to his BTC.
I think there is no need to warn the people here about CBDCs because by its definition, we know that they are not far from fiats. The people outside crypto are the ones that should be warned about it because they might prioritize it more than the cryptos. They believe it's much safer as it's supported by the governments.
It's a good thing that Brazil will allow BTC and this can surely have a positive impact in the price of the coin however people in those country should only buy BTC using other mediums and not through CBDC because like you said, they might be tracked so this kills the purpose of BTC if their primary goal is to become anonymous.