Governments like the idea cryptocurrencies are trackable, but they don't like its decentralized nature, so they are going to fixe it by creating their own centralized cryptocurrencies that aren't different from traditional fiat currencies in value, purpose and usage. I believe their impact on crypto market will be zero, because people who are investing in bitcoin and altcoins aren't interest in fiat currencies, especially from third world countries.
Dont take the people running the government to be fools, the politicians are fools, but the ones who work in background are way more knowledgeable than the average forum user here.
Now the governments already know this, so they will try to coerce people into using their CDBC than cryptocurrency. How they will do that, it will be seen with time.
Moreover, there is already stablecoins which follow dollar price, the best option of its kind and the only one needed to avoid cryptocurrency market's volatility.
Stablecoins are not a solution to this, they are an intermediary system to avoid the volatility of bitcoin and similar currencies and multiply your assets over the market movements. Beyond that I doubt how much actual usage they get. But if governments allows that then their use will increase.
Dont forget that the users on this forum are a small chunk of the entire population out there. We are a minority there.