The question here kind of implies that there are two kind of equal realities that these chunks of the population occupy but I think that is not a great framing for understanding what is going on.
The vast majority of the US population live in a very normal a-political reality that is largely untouched by narratives that drive the higher-engaged folks' perception of what is going on.
The sliver of the US population that genuinely occupy a different reality is dominated by people that occupy an almost exclusively right-wing media reality. (There is a left-wing media reality for sure, but it is microscopic, counterpunch is just not that highly trafficked!)
The riots in the capitol today demonstrated this quite clearly when contrasted with the protests that kick off the Trump presidency. The "women's' march" was a fairly clear statement in acknowledgement of Trump's presidency but a denial that it was truly representative of popular will. Today's demonstration & riot was populated by a mix of people consuming non-facts and fabulists exploiting those people. QAnon followers were prominent and appeared to be at least a plurality if not a majority of the participants. The people filming themselves in Nancy Pelosi's office were prominent neo-nazis or YouTube provocateurs (Fuentes and BakedAlasaka).
A few thousand people on the capitol overwhelmed a police force that was at least partially sympathetic and was certainly understaffed, in the alternate reality where the opposition to Trump were anti-democratic in the same way they would overwhelm any force arrayed against them in a similar way much more easily through sheer quantity, but they don't hold those views or endorse those methods.
Roughly 1/3rd of voters thing the presidential election was fraudulent, but closer to 1/5th think Trump really won according to Morning Consult, some of this is just facing the fact that the US has always been a bit of a low-trust/conspiratorial society. Some of what is going on is certainly better reporting on what is really happening - things that have actually always happened. Some of what is happening is just good old fashioned bad leadership!