I don't have an answer for this really outside of silly ones like "strict equality check", but I assert that no one else does either, at least today and right now, and its an inherent limitation due to the nature of embeddings and the space it desires to be (cheap, fast, good enough similarity for your use case).

You're probably best off using the commercial suggestion, and if its dot product, go for it. I am no expert in this area and my interest wanes every day.