The Quest for the Historical Paul

[Mudhammam]

In other words, it's perfectly reasonable to infer that Paul's reference to Aretas is consistent with what we know about Aretas IV.

No it isn't Paul said Aretus ruled Damascus, Aretus IV never ruled the city. You can't extrapolate from your preconceived assumptions to say that events agree with them, you need to provide evidence.

The only evidence, as far as I know, is that (per Josephus) his ancestor Aretus III ruled Damascus and coins found which depict Aretus IV describe him as "Aretas, King of the Nabataeans, Friend of his People," the Nabataeans a community associated with the region that historically would have included Damascus. So, nothing Paul says is inconsistent with this fact.

Your claim that he never ruled the city doesn't appear to be supported by any evidence, though.