i spent many of the pre-facebook years surrounded by people who would tell you all about tower 7 and the trilateral commission. those people were called schoolteachers.
Is QAnon prevalent? I keep reading it is, but I have never encountered it. (Edit: I just googled it, and Wikipedia claims there have been studies finding hidden Facebook groups about QAnon with millions of users. Seriously, I don't think that is sufficient proof for the ubiquity of QAnon. Edit2: the article I read, German Wikipedia, pretty much seems to simply equate people who voted for Trump with QAnon believers. No wonder they estimate their number to be in the millions. https://de.wikipedia.org/wiki/QAnon ).
I mean, even here in Germany we have people with Q signs and slogans at the corona protests, so it's not even a US-only thing, despite being focused on Trump.
Edit: You realize the Corona protests are organized by a group that calls themselves "Querdenker", so the "Q" may just refer to "Querdenker"? You just provided me with another indication that the alleged wide reach of QAnon is the actual conspiracy theory.
Even assuming that is true (I haven't noticed, but I didn't specifically look for it), it doesn't prove they are "widespread", as only few people go to Corona protests. They are a special part of the population. I don't think people happen upon QAnon stuff and become radicalized that way, as the social media alarmists claim.