Are a certain percentage of Americans brainwashed / indoctrinated by the liberal left wing media and big tech, and don’t even know it,

all american media are pretty much biased propaganda, each side thinks the other side is brainwashed by media, the truth is both are brainwashed in their own way, that's what propaganda does. you take an american republican and you can pretty much predict what they think about any given subject and you can do the same with liberals, they are both just the product of their own biased media. you want to get an objective perspective on anything? watch many international media from various countries and build your own idea.