Why would we do that though?
Like, Alduin appears in Skyrim. He is the main villain of Skyrim. He is the instigator of Skyrim's plot. Skyrim is, fundamentally, about Alduin.
Why on earth would you rely on a MMO spin off game set nearly a thousand years before the events of Skyrim as a source for how strong Alduin is, especially seeing as Alduin does not even appear in that game?
( Like, I know the actual answer is solely "because it gives bigger numbers" but like, surely you realise that what you're doing is extemely silly, right? Ignoring the source a character is acually in, and instead focusing entirely on a spin-off game that the character does not appear in is a ridiculous way to source an argument. )