The speed with which you’ll be able to create and disseminate propaganda is mind blowing. Imagine what a 3 letter agency could do with their level of resources.
I would like to suggest a different lens to look at it through. In my understanding, we merely had a very brief period of time where a probability of mass audiovisual media from an untrusted source being an inaccurate portrayal of events was low enough we very rarely bothered to actively think about it and consider if it could be "fake". Or I would rather say "artist depiction", to make it match pre-mass-photography world more accurately.
All that changes is this probability. It used to take a lot of resources to make a good realistic-looking media, now it's becoming a commodity. What required a resources available only to a few, is now rapidly becoming cheap. That's really all what's happening - the rest is all the same, our senses can still lie, and we can still believe in things that never objectively took place.
And it's only about the realistic-looking audiovisual media. Other types of media (such as texts or non-realistic graphics) had those issues since forever. And we're still mostly fine (though the rapidly increasing scale of mass communications poses their own challenges, of course, but that's a related but different issue).
There are at least two ways I beleve this will be approached:
1. Updating mental models of trust, so we don't eagerly believe random people posting videos on the Internet anymore. Not easy (especially for old timers, as we are tend to be quite firmly set in our ways of thinking), but next generations would be born to the new reality and misplaced trust won't be an issue again. The obvious danger is the instability during the transitional period - societies have huge inertia, so a few decades could get quite messy.
2. Attempt to legally or technologically keep said probability low. Trusted cameras, AI regulations, extra online policing - those kind of things. The obvious dangers are that this could have all sorts of weird implications for freedom of speech, personal computing accessibility, and could also contribute to increasing power disparity.
Whatever happens in the future is unknown. All we can do it to try our best to steer it in direction we think is right.