Why do you think this, fascism has never been defeated by armed popular uprisings. Even in the best case of the Spanish civil war where the workers were armed by the Republic, combined with the remnants of the Republican regular army and the Republican state capacity, they still lost to the fascists.
That was in early twentieth century Spain with a very small liberal middle class and huge swaths of deprived poor industrial and rural workers which faced even more deprivation under a fascist regime making them actually willing to fight. The vast majority of Americans, like the middle class in Germany, would go along with fascism if it meant they got to keep the material comfort they’ve accrued, which it probably will if it plans to succeed. Also civil war Spain had a massive labor and communist movement to organize the workers while America is completely atomized and hostile to any left organizing. Maybe 10% of Americans would rise up if the fascists started the purges, and that amount of untrained, unorganized armed mass can easily be defeated by the army.