I think people also forget that Viltumites have a similar issue to what we saw with Allen, they mostly fight jobbers and weaklings now so they probably underestimated Mark and can be caught off-guard. On the other hand, Mark has been going up against monsters >!fucking Battle Beast lmao!< almost from the start of his superhero career so I don’t think it’s that much of an asspull that he’s rapidly increasing in strength.