So the logic here is back to front.

If you're going to hypothesize we exist in a simulation then you have to offer proof. If you can't offer any proof it means we're not living in a simulation. It's excruciatingly simple.

Being unable to disprove something isn't enough to make something fact.

Can you prove I don't transform myself into a giant ape and fart rainbows every weekend? No, you can't. However, in order to prove this as fact I would have to provide irrefutable evidence. It's the same with this simulation malarkey, there's no evidence we are.