Biden can ask of Congress anything on day one -as any president can- but he can not write a law. You can take Biden’s words to mean that he himself was going to decree a change to the tax code or you can accept that his words were confined to his executive powers to ask Congress to do this.
I don’t know why sooo many people confuse the power of the president with that of a dictator. If a president can decree a law then why the fuck do we have a Congress?!