USDT ,USDC and all these stablecoins are also sorts of digital dollars though the US government does not recognize them. In case US government came with its own digital dollar, it will have no effect on the bitcoin. I would say that bitcoin will become even stronger since we know that US dollars won't be inflation free and can be produced as many as they like anytime. 

The effect of digital US dollar would be that other countries will also come up with their own stable coins, creating a mess of useless coins 

but they still think that bitcoin is a major problem of big energy use and masks the real big energy use. Bitcoin becomes the scapegoat to cover it all. Financial freedom is a disaster for governments because they cannot regulate it. Bitcoin is a financially free digital asset that is full of pros and cons, but bitcoin will survive and cannot be threatened by anything including the digital dollar that continues to emerge. Bitcoin stays on track and digital dollars or stablecoins stay on track too. The government cannot fully regulate.

The digital dollar will not pose an immediate threat to bitcoin because the digital dollar is an improved form of cashless dollar payments. The digital dollar can really compete directly with non-government stablecoins because they will have so much in common. Moreover, states may further prohibit the circulation of non-state stablecoins due to such competition.

The topic of digital dollar was discussed many times. We already have USDT, and it doesn't seem to take away Bitcoin's power. USDT is not under control of the government, and IMO it makes it better, attractive to peope around the world. The USA is a big country, but many people within it would be skeptical about the digital dollar because they prefer the one they already have, and people outside the US might be reluctant to use something that is under lots of control of a particular state which they might not trust or like.
Furthermore, lots of people are into Bitcoin because of its growth. The digital dollar would aim at stability, not growth of value, so it's a completely different thing even in this regard and thus Bitcoin users won't be tempted to switch at all.

Neither the Digital Dollar nor the Digital Yuan will be a direct threat to Bitcoin. That's because Bitcoin's decentralized and censorship-resistant design will make it hard (if not impossible) for governments to carry on with their agenda of forcing the use of Fiat for good. There will always be a way to access Bitcoin even if the government bans its use (consider how there are people mining and using Bitcoin in China even though it was "banned" by the government some time ago). CBDCs like the Digital Dollar and the Digital Euro will only strengthen Bitcoin's adoption in the mainstream world. The fact that central banks are responding with digital currencies of their own, tells us that Bitcoin is being taken seriously among those who previously ignored it.

I think the Digital Dollar would be successful because the pandemic has accelerated the adoption of digital payments by a large margin. People are used to paying with their phones or credit/debit cards without ever touching paper money, so the transition to digital Fiat should be a no-brainer. If the US acts quickly, it may be able to hold the Dollar's (USD) position as the reserve currency of the world. We'll see what'll happen after the Digital Dollar is launched for public use. Just my thoughts

Note that this is not about fiat dollars or any other fiat currency, but this thread is about the other possibilities that digital dollars could bring to a new form of government-owned payment system and will it be a threat to bitcoin?

I've already said that the traditional fiat payment system we've been using has had many setbacks, including a reduction in customer trust in banks. But what will be the impact of digital dollars or the like on bitcoin, that is the main point.

Yes, it is digital fiat that has nothing to do with blockchain. But I can think the digital dollar the OP is referring to is the digital dollar the government is planning to go through CBDC where the concept is still centralized but maybe integrated with one of the blockchain.

That can be done through the CBDC, but the government will not be able to encourage bitcoin users to stop using bitcoin. CBDC is government owned currency where they have central authority, so it is just another alternative to government currency to get more usage

Of course, bitcoin to stay - CBDC will not negatively affect the popularity of bitcoin.

In order for the digital Dollar to become a threat for bitcoin it has to become completely decentralized and also it has to be not in control of any government. Since digital dollar will be controlled by the US government there is no way to dollar can become a threat to bitcoin. I don't understand why people are comparing digital dollar with bitcoin.

The actual competition depends on the usage of people and government are still exploring the blockchain technology to develop these digital CDBC but it's not a threat to bitcoin as we have seen in China digital yuan case also.The people will keep utilising btc as mode of investment and payment in the future with the inflation rising.The digital dollar is just another form of currency only subject to government control so how come it can compete with decentralised coin? So we can say that btc growth is determined despite of these relentless efforts by governments.

Powell said he will need approval from white house and congress for process with digital dollar although it will not harm bitcoin after approval.