I believe God exists as a human construct. God does exist in written form as many characters throughout history. Sometimes as a ruler and creater of all things like in the abrahamic religions and as multiple iterations with different names ruling over one thing like in the Greek and Roman mythologies. A hierarchy of gods. One god can outrank another god.
Sometimes there are also half gods like Hercules etc. The one thing every God has in common is that they are fictional.
Uneducated masses have been manipulated throughout history to believe gods exist in a literal sense and base their lives and personal choices on their beliefs in such numbers that it has become a kind of default explanation of the unknown for the whole world.
Due to this, many educated people also believe God actually exists in a literal sense. This is due to influence from a young age and stubbornness. Some people may be embarrassed to appear wrong. Other people may appear smart but lack an ability to suspend belief and consider other options.
In science, many theories on reality and why things are exist. Some have extremely solid proof yet continue to be challenged as science is not rigid in the same way religious beliefs are. It has no rules. Science can believe one thing to be the case and then discover something else and the facts are updated.
It should be noted that God has never been proven to exist and the only proven facts to ever come out of a religious text have been certain historical events or places to have respectively happened or existed. None of these events were supernatural in any way.
So I only believe in God as far as it exists in human imagination. When the human race dies out, our Gods will go with us.