The SA so far stands to show that the central belief of broad theism is basically correct.

"The universe was created by an intelligence" is the central belief of deism, not theism. Whether or not the intelligence would interact with the universe, for what reasons, and to what ends, are open questions.

You're right, I completely agree with the above in terms of the theism/deism distinction. The SA supports deism while allowing for theism but leaving it as an open question. My term "broad theism" meant to include theism & deism. Perhaps that category already has a term, not quite sure.

Also, at this point I'm more inclined to accept Tegmark's mathematical universe description than the simulation argument.

I find the SA has much stronger support - Tegmark requires the additional belief that other physical universes exist for which we can never possibly find evidence for against.

There are superficial similarities between the simulation argument and theism, but, for example, the idea of worship/deference in the latter is a major element that the former lacks.

Some fraction of simulations probably have creators who desire some form of worship/deference, the SA turns this into a question of frequency or probability. I of course expect that worship-desiring creators are highly unlikely. Regardless, worship is not a defining characteristic of theism.

The important question is: will using theistic terminology help with clarity and understanding for the simulation argument?

I see it as the other way around. The SA gives us a reasonable structure within which to (re)-evaluate theism.