This is a very prudent question. Like, if we could somehow prove that we existed in a simulation, that would be an earth-shattering discovery about our origins... but then what?
What would we do? Some people would probably go nuts living with that information and certain philosophies/religions would have to reckon with that, but there isn't anything we could do differently, and it wouldn't alter our lived experience in any way, aside from maybe coloring it in a new light.
Not to say that seeking answers for the pursuit of knowledge itself isn't worthwhile, but... yeah, what would it even matter to most of us outside of academia/philosophy?