Any philosophical theory that has anything to do with the observable universe is inherently self-centered.

Which is not to invalidate it, but it’s not objective, and it has nothing to do with science.

The way I see it, this places quite a lot of physics into the category of "nothing to do with science." The Copenhagen interpretation of QM, for example, is based on what we can observe and detect, and asserts that particles do not have an exact position because there are limits on how closely it is possible to measure it. To me, it's the same principle.

There is a subtle distinction in my position. I'm defining existence as a relational property, meaning that what I am claiming is that things outside the observable universe do not exist relative to me. They may exist relative to someone else, although I have no way of knowing if they do. Therefore, I don't consider it self-centered.

In opinion, the thing that has nothing to do with science is making claims about things that we can't observe, because they are outside of the observable universe. How can we say, from a scientific perspective, that the universe continues beyond that if we can't test that theory? By definition, such claims cannot be considered empirical or testable.