I take COVID and long COVID seriously, but we have many examples of anti-rationality as a political problem predating the pandemic. The fact that Trump was elected as a candidate who was more about slogans than policies and achieved political success by being overtly anti-intellectual seems to weaken your theory of COVID as the sole or even major factor.

Think farther back to conspiracy theories that gained wide acceptance in earlier administrations - FEMA concentration camps, Obama isn't a US citizen, 9-11 was an inside job etc. The same patterns of ideation were laid out in Richard Hofstatder's famous essay 'The Paranoid Style in American Politics' which was written in 1964: https://harpers.org/archive/1964/11/the-paranoid-style-in-am...

...and of course you could trace them farther back through the red scare, the interwar period, the gilded age, post Civil War reconstruction, and the ideas that drove the outbreak of the civil war in the first place.

So while I agree COVID is an exacerbating factor, it's a quantitative rather than a qualitative change.