Different people mean (very) different things; but tend to assume their own belief is self evident.
For example: “God is a metaphor for that which transcends all levels of intellectual thought. It's as simple as that.” ― Joseph Campbell.
Well, that definition has essentially nothing to do with how I define God, which on the lines of the being/s who created the ordered universe. Of course, any brief definition immediately cries out for further definitions of such terms as 'being', 'create' and 'the universe'.
But the point is that when discussing God I am focused on creation as that-which-was-created by a personal God. I am not talking about everything that is - but that which is created.
I am not talking about God being ultimately physics-y concepts such as forces, tendencies, forms or the like - nor attributes such as infinities, omnis, mysticals, transcendences etc; but I am talking about a being or beings - living, conscious, personal.
I am perfectly aware that many or most other people have a completely different way of talking about God than mine - of which "that which transcends all levels of intellectual thought" is an example. But - what can I say? That is not what I mean by God, that is not what I regard as the ultimate metaphysical assumption - the ultimate basis...
There is not much point in arguing about such ultimate assumptions. I regard God as a person, another regard this is childish and regads God as an abstraction. What could decide - except to locate one's assumptions and then tease-out the consequences of one's own assumptions, and check if these entailments also are endorsed?
But what can reasonably be argued about by Christians is what Jesus meant by God. And what evidence we have on that subject (what we regard as evidence, and why). My primary objective evidence is the Fourth Gospel - for reasons given in the link. Others would have other primary authorities. (For Christians, primary authorities then need to be validated as genuine, solid, bottom line intuitions - by God within each of us (by virtue of us being God's children), and by revelations of the Holy Ghost.
We should probably then ask questions like: Did Jesus know God as a person, or as an abstraction? Did Jesus know God as a transcendent mystery, or as one person knows another person? Did Jesus see God as a personal creator, or that which is defined by attributes or abstractions?
And what relation does Jesus's knowing have to our knowing? Did Jesus see men as like Himself: children of God, His brothers and sisters, his friends? Or did He see Men as qualitatively different from Himself, inferior beings such that Men cannot know God in the same ways that He knew God - and for whom God can therefore only be a transcendent mystery, a negative-not-known...
To ask is to answer - it seems to me.