There's a great AU fanfic in here.
(1) He and his family wouldn't make it public immediately, they would work with their lawyers to work out what could benefit them the most. They'd then make demands that the SGC retrieve a functioning sarcophagus for "study" (in actuality to perpetually restore Trump and his family). The side effect of repeated sarcophagus use - narcisim, erratic behaviour, reduced empathy - would go unnoticed. SGC commanders will object, and be summarily replaced. The SGC will also be under orders to withdraw from the IOC.
(2) When the sarcophagus is secured, he'd go public with the TRUMP STARGAGE PROGRAMME. He won't mention the dangers (bad PR) but all the tremendous job opportunities and colonisation potential to make "Planet Americas" and to Make Them Great Again. A group of MAGA loyalists volunteer to become new pioneers.
(3) The threats become apparent, and the MAGA colonies are attacked - or maybe they started it, its unclear. Shocking and terrifying footage is broadcast. Trump declares war against the galaxy, and is granted emergency war powers by the Republican Party (the leads of which now have their own Sarcophagai). All elections are suspended as Trump alleges that the Democrat party have been infiltrated by mind-controlling parasites, which his base absolutely swallows up.
(4) Five years later, a Goa'uld ship lands on Earth, wishing to make an alliance with the powerful narcissistic ruler of the Tau'ri. To their shock and confusion, the tyrant ruling the Earth, full of contempt and malice, is no Goa'uld at all, but actually just a human called Trump. The President immediately tries to sell out his own people. They kill him and take the planet.