It is not strictly meaningful to ask "are we in a simulation" since there are copies of us both inside simulations and outside of them.
Take my usage to mean: "is our most outer copy in a simulation?"
The most outer copy is never in a simulation, since the content of any simulation exists in the Tegmark IV multiverse as a universe in itself.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.