I think Number 4, or the jump from 4 to 5 seem to be a simple fallacy. Because to justify 5, 4 would need to read 'if and only if...' As it stands, 4 does not rule out gods that are logically impossible but also not contradictory. (Magic unicorns don't contradict anything either, but the author of your link considers them logically impossible, I guess because he says so.)
These kinds of 'proofs' really don't speak to people who don't already believe in a god. They are fundamentally about just defining a god into existence.
To me, this sounds like pure gibberish with a little begging the question thrown in.
I followed the link to read the explanation... The author just dismisses the idea that gods might be like magical unicorns as a non starter with no discussion. He might as well have just said 'nu uh!' But it seems to me quite possible that gods are almost exactly like magical unicorns.
If I had read Kant, I might suspect that 'pure reason' without any anchors can defend any premise, true or false. So I don't even know why 'logically possible' is considered a high bar. Nor do I know how anyone could declare something like a god to not be 'logically impossible' if logic can defend any position. I suspect gods are in fact impossible, whether or not they are 'logically impossible'.
Likewise, zero conversation about why the concept of a god is not contradictory. This is just an assertion, not an argument. And I'm not even clear what is being asserted... What would constitute a contradiction in this scenario. Nothing is inconsistent with the existence of a magical supreme being?
You might as well sum up all your proofs as:
If Angel says a god exists, then a god exists.
Angel says a god exists.
Therefore a god exists.
It's a valid 'proof' but not a sound one to anyone who doesn't accept the premises.
Is the point of these proofs to convince anyone, or just to feel smug about your position? I don't see how your proofs would convince anyone not inclined to believe and just looking, rather desperately, for a justification.