The analysis video was weird. But you have to discount that under that 1) he had just lost a winning game, so probably pretty tilted 2) he was already in the eye of the storm about Magnus 3) he might just be a bit of a dick personally.
If a position has 1 winning move out of 10, you have 10% to nail it even if you are a bozo. I'd say that as a good player you'd do better than random. So while unlikely he might have just got lucky against Magnus (if we want to assume the impossibility of him just having become good).
I agree with parent that the accusation is terrible. 1) it comes from someone in a position of power, 2) it comes from someone who is party injured in the matter (saltiness factor) 3) is completely unfounded as of now. There are just suspicions and theories. 4) it's playing with the accusation without committing to it, kinda like "ill commit only if it's convenient to me". 5) his prior cheating is immaterial. Especially as a child. No one cares that he "has cheated", the point of the matter is "did he cheat in this instance".
Is it bad optics that the guy beating Magnus as an underdog is a known past cheater? Yes. Is it relevant to "he beat Magnus here"? no.
Innocent till proven guilty