As far as the utilitarian argument in favor of religious belief goes, the simulation hypothesis doesn't seem very useful. The utilitarian argument includes the notion that 'religious texts are fairy tales intended to teach moral behavior to children, and that were invented by humans alone' (a view that some find offensive, oh well).
Simulation arguments are a useful concept regardless, since a little thinking will reveal that there are an infinite number of such metaphysical theories on the nature of reality that are by definition untestable via scientific experimental methods. A perfect simulation is undetectable, comparable to claims that supernatural beings (or UFO aliens) are constantly intevening in our physical reality, only they're careful to only do it when nobody is looking.
Thus if we accept these metaphysical theories (including all religions and the doctrine of atheism) are equally (in)valid as they cannot be tested, we are left with their moral doctrines as the only basis to distinguish them from one another, value wise. We might as well include the moral doctrines included in literary works (e.g. Lord of the Rings and the Silmarillion could form the basis of a new religion).
However, if we look at the simulation theory from a moral perspective - well, it's problematic, in that it could be interpreted as support for the viewpoint of a sociopathic megalomaniacal narcissist. If you're the only real person in the simulation, and all others are non-player-characters, then it doesn't matter what you do to them... hey wait is this why the simulation hypothesis is so popular in the tech bro billionaire world?