Thirty seconds is about 75 words
People write pitches they could never say. Read one aloud and the ones that are too long become obvious immediately. The target here is what a person can actually deliver in half a minute without rushing.
The structure that works: the problem the listener recognises, what you do about it, one specific thing that makes it credible, and a question. The question matters because the goal of a pitch is a conversation rather than a decision.