Your analysis is both good and flawed at the same time.
When considering an armed conflict of two “armies" engaged in battle, you are correct. It won’t play and is even laughable on many levels.
However, that’s not the only avenue or option. Your analysis did not consider guerilla warfare, cyber warfare, or acts of terrorism or assassination to destabilize the government. These avenues require less organization, manpower, or resources.
They do require a long timetable, a mastermind, and a following. Trump has one of those things and he squandered his time; if he could think like Osama bin Laden he could’ve been in office as long as he wanted because there actually is a path that could keep him in the White House that stands a good chance of success and could be executed by an organization like the Proud Boys. IF, if you didn’t have any moral qualms about doing it and you were prepared to accept the outcome and the consequences.