Yes, this is somewhat worrisome. Would be totally worrisome if he could actually do it.
An amendment cannot be abolished. It must be repealed by a new amendment. A new proposed amendment must be approved by a 2/3 majority of both House & Senate.
That won't happen. The end.
Now a coup....well...
Depends how many people they "accidentally" disenfranchise while holding those massive military roundups they want to do. But hey, who cares, it's the vibes, man.
Here's the thing, though - these laws only work if they're enforced.
Trump has established that he intends to fill the government with his loyalists.
The GOP won't stand against him.
SCOTUS has basically ruled that the 14th Amendment doesn't apply to him.
So, who's going to stop him?