There's huge pink elephant that I think many aren't aware of here.
A former chess world champion, Vladimir Kramnik, has turned into a sort of self satire seeking out cheaters in online chess. Basically everybody is cheating according to him, he even implied Hikaru Nakamura, the 2nd strongest player in the world, could be cheating.
Eventually his sights fell on Danya. At first I thought they were both kind of playing it up as a sort of a joke. For instance after the accusations Danya did a video where he had something absurd like a dozen different cameras watching him play from different angles. And in response Kramnik mentioned some petty absurdity that I can't even recall at this point - maybe there was a laptop on a chair or something? 'What is that computer Danya, suspicious, him?' And this sort of nonsense continued on for some time.
I still think Kramnik is doing it as a half-serious joke, but Danya clearly took it very seriously. He believed that his reputation had been ruined (even though just most people think Kramnik is the one who has mostly destroyed his own reputation and mostly just seen as a bit 'kooky' now a days) and Danya became a dramatically different person over about 2 years.
Previously he was kind of a happy go lucky blitz obsessed guy. But he gradually became increasingly morose and insecure. He also seemed to be losing weight, though I have no idea if that is accurate - I'm basing it solely on outside appearances which can be misleading. In any case, this was almost certainly related, and it makes the whole situation far darker.