The Prescence & The Overvoid

Yes, they're pretty much the same being. One could argue for the Overvoid being a non-sentient place now though. The Presence could be argued to be a manifestation The Source takes though. The external forces mentioned below that shaped, not created The Presence are just the minds of humankind, the dreams shaping The Presence into their idea of a supreme being using the power of The Dream of The Endless

By Over void do you mean the Over-Monitor? The Presence was in fact created by external forces. These forces was The Over Monitor. The Over Monitor consists of the entire DC Omniverse