I've not read it myself, but my understanding from others of the comics leading up to Secret Wars is that he has a lot of servants who dress like Doom, more as a way to honor Doom and confuse enemies than as multiversal variants. Couldn't that be all this is? Of course, there is also precedent for multiversal variants in Loki, including a female Loki. So could see this going either way. I absolutely hope ComicBook.com is wrong that Tony Stark and Doom are not variants in some way (or that there's some other interesting in-universe explanation for them looking the same, whether cloning, or something). Otherwise, is it just supposed to be a wild "coincidence" that Stark and Doom look alike? That would be terrible. I could live with it, but I'd be very disappointed.