Can you point me to where they said this? I didn't hear that, I just heard them say he's playing Victor Von Doom. I never heard them discuss variants at all.
In the aftermath of the announcement there was information from an article from Daily Variety that was being misrepresented by posters on several subreddits and other outlets that made it sound like they had definitively said he was not a Stark variant. The article does not actually say this.
I don't have time (or really the inclination) to obsess over this stuff like I used to, and just kind of assimilated it as fact after seeing it claimed at several different places.
So there's still a possibility he could be a variant.