I heard from someone about the relativity of spacetime, time is slowest near the center of a huge gravity source like blackhole so out here earth time is actually relatively fast and are speeding up due to expansion, as the further our galaxy/universe is flying apart the less mass and less gravity can slow them down

So our relative spacetime scale of a billion years here, might just be a few hours inside some of those crazy dense SUPER MASSIVE blackholes

And with that in mind and some loose sense our whole simulation might just took 1 second of the creator's relative time because...time is relative , just a loose assumption