Society is going to have to adjust to actually demand some proof of authenticity when it comes to content like this.
The good news is that techniques like public-private key cryptography do actually provide a way to do this, so at least on the technical side, this is a solvable problem. The harder part is getting people to question content that they want to be true, like political propaganda that affirms their own beliefs and biases.
Just imagine the mess we'll be in when you can just generate an unlimited amount of videos of some disliked minority committing fake crimes and send them directly to people that you know will be receptive to radicalization, since you've already identified them through data brokers and targeted advertising.
Maybe this is just me getting older - hell, it probably is - but I'm getting more and more detached from tech in general and trying to find more meaning and enjoyment in real-life interaction, community, friendships, and connection, as well as more physical hobbies. I'm not convinced that humans are really equipped to mentally handle the world we're creating, and I'm finding myself not wanting much to do with it.