Question

Hello Rabbi,
I wanted to ask a question whose answer I haven’t really understood. I asked it elsewhere here on the site, but it seemed to me that the discussion there wasn’t really related to the topic, and the answers also weren’t completely connected to the question. I’d be glad if the Rabbi could answer.
If we have before us something complex and well-ordered (like a watch), but ancient [for the sake of the discussion, a heavenly voice came forth from Heaven and revealed this to us], is it reasonable to argue that it requires a designer? 
The advantage of claiming that there is a designer is that this claim has great explanatory power. It explains very well why the unique phenomenon before us exists.
The drawback of this claim is that, to some extent, we are just pushing the complexity argument one step back. After all, the second complex thing (God, for the sake of the discussion) also requires an explanation—this too is a unique entity, and we could imagine a different reality instead, and so on. So in order to stop the chain, why not stop it at the watch?
B. My assumption here is that even for an entity that is its own cause, one can still imagine that it might theoretically have existed in a different way. Could there be an entity such that it is impossible to conceive of it existing in any other way? What is the status of such an entity called? Just “necessary existence”? Or is there some intermediate possibility: that insofar as the entity exists, it could only be this way?
Is it relevant to ask the physico-theological proof regarding such an entity? If not, then we have here an excellent regression-breaker, no? 
I would be very happy if the Rabbi could address the question. (And of course the dear readers here on the site as well 🙂 )