The latest major failed coup that I can remember would be the 2016 Turkish coup d'état attempt, and the effect it had on the country is well known. The general consensus internationally seems to be that the efforts by their government to stamp out their "terrorists" has been a bit of an overreaction, even if literal tanks was involved. The censorship machine in particular has been quite overreactive.
One can really hope that the US democracy manage a more appropriate reaction that is more proportional to the threat.
He also claims that Trump is refusing to leave and is leveraging the military to facilitate that. That's bunk.
What's mostly bunk here is that you think that this is behind you and I am not willing to accept that until we have seen one, and preferably two transfers of power without mishap, preferably in both directions.
Claiming there was fraud in the past election, that the election was stolen, or that the results should not have been certified is not mobilizing the military. It's not even illegal, it's part of the constitutional process.
Hell, some Democrats did exactly that to Trump in 2017. Even the Democrat Speaker of the House Nancy Pelosi herself disputed the results in 2005 yet she now claims that anyone else repeating her own words is an insurrectionist.
The most dangerous thing you can do now is to think this is behind you and from here on in everything is normal. It isn't and it probably won't be for some time. If you manage the next two transfers of power at the end of election cycles without further mishap I'd say that you can say democracy is intact. Until then all bets are off.
Edit: I wished I could locate the article, so far no luck.
edit2: finally found it in my history, this article was from 11 November 2020, and very prescient:
https://indica.medium.com/i-lived-through-a-coup-america-is-...