This is not the workflow being discussed. Yes, you can use Pandoc Markdown (in which you can embed LaTeX) and then Pandoc can parse the markdown and produce a LaTeX file. But the actual typesetting is still done by LaTeX; here Pandoc is basically just a preprocssing step.

what was being discussed is using Pandoc to convert from Typst to LaTeX, which it can't really do because its internal document representations are not as expressive as either Typst or LaTeX.