Scenario 1 seems to be somewhat delusional - since the USA has never really been a free Democracy and voter suppression is still alive and well along with good old jerrymandering. For this to change would require a massive change.

I don't think China would want to over extend and would rather consolidate - it does a vast amount of trade primarily to keep the domestic audience happy rather than anything else. And there would be regional powers such as India / Russia and Europe in some form or other

I would imagine separate silos in a sort of love-hate interdependency / competition between different blocks which might even trade as they compete - the USSR bought grain from the USA and Canada after all.

Whether some parts of the world are ungovernable wastelands (as they are now just worse) or not will be interesting - will there have been the will to rectify the situation or will the edges be patrolled by mercs and drones to keep the masses back. Mind you, the same scenario might hold true in several states in the USA.