How do you handle crossover splats?

Going by each edition's presentation, Mage and the Technocracy should just hard dominate everyone. Even a single loose Mage can pretty much crack open reality at the same stage a Vampire is getting the ability to mindwipe people or soak your average trash fire (as long as they have blood lmao). Any inclusion of Mages into a story would necessarily mean they either need to be a particularly weak Mage, busy with something far far more important, or you to fucking nerf those little bastards. Including things like Changeling or Fallen just makes this even worse, where a 200exp Vampire Ancillae is typically going to get fucking bodied by some guy who's been here for a month tops.