These incentives already exist. The tax code has been manipulated to encourage or discourage behavior since at least WW2. A digital currency makes a lot of these incentives easier to create and easier to enforce, but they wouldn't be new.
The Federal Reserve is a bank. And we already have a relevant historical example to examine, postal savings accounts. I'm not aware of any special power that the executive branch had to bypass the judicial branch where those accounts were concerned, versus privately held accounts. Plus, the Post Office was directly answerable to the President then, while the Federal Reserve has never directly answered to the President. This is an unfounded fear and doesn't reflect anything intrinsic to a (central bank-administered) digital currency.
Not for consumers and non-bank businesses it isn't. You don't have an account at the fed. You have an account at plain old commercial bank. Someone at the plain old commercial bank can freeze your money, right now. You'll have to sue, go to court, win, just to get access to your money.
If the fed becomes the place you have an account, they can do what the commercial bank currently can do.
The difference is incentives - why do it? Commercial banks have no incentive, and in fact have the incentive to push back when asked.
As for the president - sure - generally speaking the fed is independent. But they have significant regulatory and supervisory roles all by themselves, and are part of the administration of the government even if they aren't "part of the administration" as the term is usually used in the US.
Commercial banks answer to the government, to the central bank, to their shareholders, and to their non-governmental regulators (payment networks, insurers, etc). This has created plenty of examples of "debanking" of businesses and individuals who bring with them excessive risk due to their history of attracting controversy and/or legal trouble.
Whereas, the government can of course confiscate assets already, including through commercial banks, but generally cannot refuse service. If a CBDC becomes the norm, an account held at the central bank becomes a right, and thus refusal of service becomes a punitive measure subject to statutory and constitutional limits and scrutiny. This is arguably better than the commercial bank situation, where "business risk" is (generally) a valid reason to refuse to provide service.
The incentives/goals are the issue. By and large, commercial banks want to do business with you. They are subject to constraints, but they want to do it. They can/do also push back, they aren't just doing whatever the government says.
