He is actual rather than potential and therefore cannot not be. i.e. that is His sufficient reason.
It's logical that something is potential until it is actualised and that leads back to an actual actualiser that is never merely a potential.
Whether that is a temporal heirarchy or a vertical heirarchy of dependence.
Hand-waving gibberish. Where is any actual reasoning?
Because He cannot not be. Can one say that of the universe.
Of course we can
say it, every bit as easily as we can
say it for some imagined god. Your problem is actually making an argument that establishes why we need something that cannot not be, how it's even possible that something cannot not be, and why that applies to your god and not anything else.
The floor is yours...