The problem as I see it (and hasn't been mentioned by others) is that they don't need the 14th amendment; there is also 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.Someone first needs to indict someone for insurrection under this federal code, not the 14th amendment.
-PJ
Agree, but again, that code’s intent was related to the Civil War. Context would take all of these challenges off the table, which is why so far 2 cases have been tossed, one could have been appealed except for money.