The word “God” means “That of which nothing greater can be concieved”. So, the greatest thing there is, is existence itself. The universe, multiverse, or whatever proves to be the whole of existence.
I’ve never really liked God being represented as a big bloke with a beard or anything like that… I guess I feel that any attempt to describe or depict God detracts from what God is, so there’s no real reason for doing it, apart for making Godhead easier for us to understand. But if by attempting to describe it we detract from what it is, just so we can understand it better, then we aren’t understanding the real thing anyway.