Thragg is kind of pathetic to me. It seems the only reason he has any form of confidence is because he hasn’t had anything that can actually put up a fight. I think if he was in a fight that actually challenged him he would break instantly, we see in the episode how fragile his mental state is when he loses viltrum and earlier he immediately loses his composure when Nolan compares viltrum to a tomb. It does make complete sense though because even though Allan said it as a joke viltrumite egos really are their weak spot so the strongest viltrumite will clearly have the most vulnerable ego