This is tough one. Normally i would say that it shouldn't really have much of an impact, if anything it should help create more public awareness, interest and debate on bitcoin( which always a good thing IMO). 

Now I don't really think a CBDC will harm bitcoin because bitcoin largely caters to a different market (those focused on privacy and sound money principles which is not something you would get with CBDC's  in fact it would only make it easier for sates to monitor everything you do.)

However i feel that CBDC could negatively impact Bitcoin ( at least its price) through tether. CBDC's could very well be a competitor and alternative to the swath of stable coins currently on the market and most of the KYC or heavily regulated exchanges (coinbase) could be expected to create trading pairs with a US CBDC. ( this would also mean more money flowing in to crypto in general since it would make it easier for the masses to enter)

Again the impact here would largely be dependent on your thoughts on the solvency of tether. It could be the nail that brings it down or it could finally be what gives the whole market a more trusted stable coin ( at the cost of less privacy and  more regulation)