That isn't an argument, it's an assertion of definition and identity.
The Supreme and Ultimate Reality is God.
And here is another assertion. If you take God as being anything other than this, you are not talking about the God I believe. You are also not talking about The God that theology accepts. You are talking about something else.
So you can argue about the meanings of words all you like, but you would be the one who is in error, not me.
I know what Supreme Being means. I know what Ultimate Reality means. I know what The Truth means.
It means saying God doesn't exist is not a valid position. You are automatically wrong, and so is any argument, no matter how clever, that either builds off of or attempts to prove this ridiculous and patently false position.
And by the way, it is self defeating. You can't say that it is true that there is no truth. That is what you are quite literally doing if you say, "There is no God".
So believe me when I say this isn't something worth debating, because there is no argument against God. But if you don't understand what I'm telling you, go ahead and argue with futility. If you'd rather arbitrarily strive over the meanings of words, go ahead, but you are wrong. The only argument against God is to make God a god. An idol. A straw man. If you understood the concept, you'd see this very clearly.
And I would much rather see you confess The Truth than make a fool of yourself.