Always a fun topic this one.
I used to be a believer in this theory, but now I'm more on the indifferent side. If anything, I'd be more obliged to say it's a simulation of our own creation. That which we manifest in our mind, manifests in our reality and w/e.
But frankly, so what? If since we live in some great computer, biological entity, or energy prison, why does it mean that we can't enjoy out stay? I pose a question. Why do you still live for a future, and dream about one, if you believe that A) in context of this theory, it is insubstantial and meaningless, and B) is nevertheless uncertain in the face of death? Death can and will come at any moment, regardless of the state of the universe, so I say live for your now. If you don't believe in the future, you have total, complete freedom to live for your now. Become a crust punk and ride the rails, go backpacking across the country with nothing but the posessions on your person, fix up an old van and see all the natural wonders we have at our fingertips, that people of yore could only dream of. Buy a sailboat lmao. (Just kidding on that last one)
It's kinda a mass delusion that everything we do is to work for our future. Even in taking the well trodded path of building a career and etc, you are still working for your present. Comfort, health, family, etc, granted many people go about this in an unhealthy way, which is not their fault, it's just the most common thing in this stage of humanity. So, in working for the future, you're working for your now. Why bother continuing your current cycle if your now sucks? Live for the present, as it's something we will always experience, and the only thing we truly have. Always find a way to seek your happiness in the present, and you will live a perfect life. Many people find this happiness in productivity, which is a good example of a healthy present. Many people find it in drugs, an unhealthy present.
Now nihilism, which seems to be a very common theme, if not core tenet in this simulation theory, gets close, but misses the point. This isn't meant as a personal attack, and is said in kindness, but most nihilism is just depression shrouded behind a delusion of intellectualism. It's a mental virus, a cognitohazard that sucks you in. And, as it sucks you in, it becomes harder, and harder, and harder to crawl out of. To the sufferes of this, again, don't take this as a personal attack, it's not your fault. There is nothing to blame. It's like a disease, you can't blame the disease, it simply is. But as it's a disease of the mind, not the body, the immune system will not fight it for you. Only an immunse system of the mind can help.
Meandering like a river lmao, but basically my opinion is thus: If we live in reality, great, it's a perfect opportunity to live your best life. If we live in a simulation, great, it's a perfect opportunity to live your best life.