The best thing about HOI4 is the unofficial, fan made, stories and scenarios you can find on the Steam Workshop.
I'll start off with an obligatory mention of the new "most infamous" mod on the scene. "The Fire Rises".
2020 happens, but it's worse this time - and everything goes to hell in a handbasket.
A Second American Civil War - between Trump, Biden, and a million different splinter factions.
China tries to invade Taiwan, and depending on what happens, any number of strange scenarios can play out - one involves the automation of many industries under the watchful, mechanical, eyes of "LoJi" - a sentient AI with an Anime pfp.
All of Europe descends into a war between NATO and Russia - twice.
To be honest, were I to list all of the crazy shit in this mod I would be here forever, so I'll just embed a teaser for a faction that will be playable in the next major update - "The Green Mountain Company".
It's a Private Military Company based out of New England that can take over America during the Civil War - and then turn America into something akin to "Outer Heaven" from the Metal Gear series.