They don’t mention the talk that Xi had had his wings clipped in China. That could explain why he’s not showing up.
There are two schools of thought emerging about the dark maneuverings going on at the highest level in China: either xi is consolidating his power, or he is on his way out.
A murderous dictator's lot is not a happy one. He must always fear revolution and a palace coup. Paranoia must be a constant corollary. Brazil is a long way from China and it might be hard for Xi to watch behind his back from there.
Plus Putin had to send his hatchet man Lavrov in his place, for fear of being arrested as a war criminal.