If we are indeed living in a perfect simulation, perfect in the sense that we are unable to detect that it is in fact a simulation, then we have to live as if what we perceive is "reality", because our perceived reality can kill us. It effects us in concrete ways, obviously. We have to treat it as "real".
So we do have to figure out how to reduce and adapt to climate change, and make sure we get enough food every day, and continue to try to understand how the universe works using science, because that is how we will ensure our survival. Our survival will not be ensured by ignoring climate change, by memorizing ancient religious texts, by ignoring what science tells us about how the universe works.