I don't understand why a GM would need to explain some of his moves precisely and with a deep understanding of the position as some commentators here point out. Why is that so indicative of cheating? It's known that classical chess has a lot of theory, and Hans himself admits that he checked an engine line the evening before the game. So what? Here's the quote:
"
I didn’t guess it, but by some miracle I checked this today, and it’s such a ridiculous miracle that I don’t even remember why I checked it. I just remembered 12…h6 and everything after this, and I’ve no idea why I would check such a ridiculous thing, but I checked it, and I even knew that 13…Be6! is just very good. It’s so ridiculous that I checked it.
"
https://chess24.com/en/read/news/sinquefield-cup-3-niemann-b...
" I didn’t guess it, but by some miracle I checked this today, and it’s such a ridiculous miracle that I don’t even remember why I checked it. I just remembered 12…h6 and everything after this, and I’ve no idea why I would check such a ridiculous thing, but I checked it, and I even knew that 13…Be6! is just very good. It’s so ridiculous that I checked it. " https://chess24.com/en/read/news/sinquefield-cup-3-niemann-b...