It is often claimed by theists that without God (abrahamic God, choose any definition you want when responding) there is no objective value to human life, or there are no objective morals. But I'd like to suggest, that even with God there is no objective value or morality.

Why is God not just the most powerful subjective agent in existance? The most common idea I've seen is that humans have value because we are loves by God, but it is never coupled with a reason why God's love is a source of objective value. What if I just don't give a shit about what God loves, wants, or thinks (permissing slavery does not incline me to care)?

I also hear that God created us, and so it is moral to do what he wants/what we were designed for. What if we discover that we are actually created by a deceptive demon, and it wants us to commit what we would view as atrocities? Would these atrocities become moral?

Its often assumed that God is a source of objectivity and thiests put it on atheists to show how we can make any objective claims without God. But I think we are in exactly the same boat when it comes to objectivity, and our lack thereof. And in my opinion it is not a terrible boat to be in.

I struggle to fully explain why I disagree, but really the burden of proof is again on theists. They claim their God is a source of objectivity, and I have not been given a good argument why. If you are aware of any even half good arguments please share them I'd be interested to know. Or better yet if you think God is a valid source of objectivity please provide your reasoning.