https://www.insider.com/all-the-us-capitol-pro-trump-riot-arrests-charges-names-2021-1
Though the researchers include the fact that the overwhelming number of people live in Democrat areas, they also highlighted the fact “that proximity to Proud Boy chapters and local levels of engagement with misinformation posted on Parler, the exiled social media platform popular with the far right, are robustly linked to participation in the Capitol rally.”
So they may not have been Qtards, but that is how they obtained their information.
and 300 is a very small number to the whole.