18 U.S. Code § 2383 - Rebellion or insurrection
Whoever incites, sets on foot, assists, or engages in any rebellion or insurrection against the authority of the United States or the laws thereof, or gives aid or comfort thereto, shall be fined under this title or imprisoned not more than ten years, or both; and shall be incapable of holding any office under the United States.
18 U.S. Code § 2384 - Seditious conspiracy
If two or more persons in any State or Territory, or in any place subject to the jurisdiction of the United States, conspire to overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof, they shall each be fined under this title or imprisoned not more than twenty years, or both.
I'm not sure I see much of difference, except that §2384 requires a conspiracy, while it's enough to incite by yourself to be convicted for insurrection.
§2383 can be applied if you get caught in the act; for §2384 to apply, you don't need to have acted yet, it's enough to have conspired to do so. You can convict the conspirators for sedition even if the rebellion hasn't started yet.
I'd hesitate to call anything a coup that isn't associated with a change in power; but Trump already is the commander-in-chief, so it feels like the word wouldn't really apply before Joe Biden takes office.