QAnon wasn't created an popularized by some institution repeating a lie. It isn't even propaganda per se, it's a grass roots conspiracy theory, fanned by propaganda on certain particular facts (such as election fraud). It's the result of decades of bigger and smaller lies and truths being spun by various forces until they coalesced into this mess. There isn't some central Big Lie that QAnon believers have been fed, except perhaps the oldest lie - it's Us vs Them, and We are righteous while They are evil.

"Q" wrote his initial lies once, and people ate it up and spun it around among themselves. This is folklore, not propaganda.