The objective truth of existence, that is, the way everything really is, will be that way whether or not someone experiences it. To say otherwise would be to say that if a tree fell down in the woods, and no one heard it, it didn't really fall. That no-one heard it does not change the fact it fell down.
However, you are correct - we cannot meaningfully talk about the objective reality, even though we can be sure it exists. By "it" I am not referring to a god, or an omniscient and eternal being, as you have posited. Rather I