This kind of question has surfaced on the forum before, and the answer is simple, it's a threat to it, but the threat would be minimal. A threat in the sense that many that are using Bitcoin for particular reasons like payment and investments might want to divert to the US Central Bank Digital Currency (CBDC) because it's better for investment in my experience and would be more readily available for that purpose. But for payment, this would depend on the offers the digital currency comes with. If it's such an offer with zero to a low transaction fee, more people would adopt it in place of BTC.
The main strength of BTC is in privacy and anonymity, and it would use that to continue to secure its place amongst rival payment systems.
If compared as a means of payment, bitcoin today is still not widely used because most people prefer to accumulate and hold bitcoins than to use it as a payment method. If compared as an investment, it is clear that CBDC does not have any effect on bitcoin, as CBDC is fiat, just a currency but in digital form.
So I believe CBDC can't threaten or affect the development of bitcoin, when CBDC comes out, instead of using fiat, we will use it for daily activities. BTC and CBDC are entirely different.