Somebody has not been reading the fictional book they are ranting against, I see.
Characteristics of God, as defined by the bible:
Is the beginning and ending of all things.
Created the physical universe (not just the earth.)
Used Jesus as an avatar to accomplish some goal in heaven (not well stated, just that jesus's sacrifice satisfies some set of obscure laws in the divine realm)
"Is literally all things"
Those describe an extra-universal entity, which contains our universe. A thumb on a person's hand is not the person. It is a thumb. Searching the thumb for evidence of the whole person is logically absurd. However, the person can freely manipulate and even mutilate the thumb at their whim. The teapot analogy people are basically implying that not exploring something that can be explored is the same as not exploring something that cannot be explored. They are not the same thing.
"God" can exist as described, and satisfy all of those features, by being extra-universal in nature. It simultaneously explains how this entity is both beginning and end, is omniscient about the past, present, and future of our universe, and yet still seems bound by some set of laws and conventions.
Like many, you fall victim to preconceptions about the religion, rather than critically thinking about what is actually being stated in the religious texts. EG, what is actually written, vs the dogma associated.
Again, I am an agnostic, and a hard one at that. I dont KNOW that there is an extra-universal god, nor that our universe is merely a component thereof-- I am just pointing out that such a theoretical model holds with the description, and that your argument does not hold against such a circumstance.