Republicans want to ban abortion nationwide, but they are unlikely to be able to do it even with a trifecta, unless they decide to abolish the filibuster, which many Republicans don't want to do (because they know they will be in the minority in the Senate from time to time). But there might actually be an easier way, and it doesn't require Congress to go along at all.
Here's what a Republican president could do. In 1873, Congress passed a series of laws known as the Comstock laws. They criminalize the use of the U.S. Postal Service to mail obscene material, contraceptives, abortifacients, sex toys, and even personal letters with sexual content. Parts of these laws have been nullified by Supreme Court decisions, for example Griswold v. Connecticut, but the parts that have not been struck down are still on the books.
The Heritage Foundation claims that the Comstock laws ban the mailing of mifepristone and misoprostol. The Biden administration disagrees and issued a memo on Dec. 23, 2022, that includes the wording: "Because there are manifold ways in which recipients in every state may lawfully use such drugs, including to produce an abortion, the mere mailing of such drugs to a particular jurisdiction is an insufficient basis for concluding that the sender intends them to be used unlawfully."
However, a future Republican administration, whether under Donald Trump or someone else, could withdraw the memo and write a new one stating that m & m drugs do fall under the Comstock laws and therefore cannot be mailed legally. The government could then make it clear to pharmacies that they will be prosecuted for mailing them. One possible work-around would be to mail from pharmacies in other countries, for example Canada or Mexico. The legality of that might be iffy, but would be hard to enforce, especially if packages from Canada were in boxes labeled "Maple syrup."
Of course, if a Republican administration took this view, there would be lawsuits and it would be up to the Supreme Court to determine what the laws mean (as usual). When the Supreme Court knocked down Roe v. Wade, it left the decisions about banning abortion up to the states. If it were to uphold the Comstock laws, it would be taking the decisions away from the states and giving it back to the federal government again. That would be inconsistent with the Dobbs ruling, but who cares about consistency when you have an axe to grind. (V)