You make reasonable assumptions, but proving them is hard, because any attempt you make to prove them still end up being filtered through your potentially unreliable senses.
In practice we decide to just accept that a material world with semireliable senses exists, because the alternative is no certainty at all.
"The Simple Truth" addresses this from a different angle: https://www.lesswrong.com/posts/X3HpE8tMXz4m4w6Rz/the-simple...
There is no possible experiment you could in principle do to verify that the universe stays the same when you're not looking. We can say that the universe behaves consistently as though it does, and I'm not saying that doesn't matter, but it's not quite the same thing. Furthermore we can't tell whether the universe is tricking us some of the time, or all of the time, or never.
And then people invented video cameras to trick the universe to stay the same when they go to sleep
Proof demanded.
We sentient beings are fortunately capable of discussing abstract thought, things not known to exist, and even things known not to exist; we can give them names without requiring that they 'are', and we can discuss what it means 'to be' anyway, and whether those things 'are' after all merely by virtue of our discussion.
And did you even read the rest of that sentence? Other commenter is basically 'on your side'.
It's atheism like this that makes me describe myself (dissociatively) as agnostic, frankly.
The state of an individual person’s consciousness has no bearing on whether the sun is shining or not.
Refrigerator lights turn off when the door closes. It’s usually easy to find the mechanism that handles this and manually trigger the light to switch off.
Regarding God, I assume you mean the Abrahamic god. There are many culturally specific deities and superstitions and there doesn’t seem to be any verifiable reason why one would be “realer” than any other.