I think you've described the problem (or one of them) very well.

We've seen how misinformation -- including ideas that were once fringe, believed only by a minority of cranks -- spreads and becomes acceptable, becomes a "legitimate alternative opinion".

We've seen, too, how hostile states, populists within, spread falsehoods to sew havoc and division.

My only hope, really, is that I think some of the younger generation are slightly more alert than some Gen X and millennials (my own generation) as to the dangers of misinformation online.

I wish I knew the solution too. Like you, I feel quite helpless even in terms of what to WANT. Can the Twitters of the world be regulated? If so, are we as a society able to agree on how it should be regulated, or are we too divided to agree on anything?

It's a mess. I don't know how we get out of it.