It’s possible yes, but the nice thing is that we know we are not merely talking about “advanced people with vastly superior technology” here. The proof implies that technology within our own universe would never be able to simulate our own universe, no matter how advanced or superior.
So if our universe is a “simulation” at least it wouldn’t be an algorithmic one that fits our understanding. Indeed we still cannot rule out that our universe exists within another, but such a universe would need a higher order reality with truths that are fundamentally beyond our understanding. Sure, you could call it a “simulation” still, but if it doesn’t fit our understanding of a simulation it might as well be called “God” or “spirituality”, because the truth is, we wouldn’t understand a thing of it, and we might as well acknowledge that.
I was pointed to Georgism the other day: https://en.wikipedia.org/wiki/Georgism
I’m starting to get convinced about it, even if there are aspects I haven’t fully wrapped my head around yet…