Every document parser must first answer this question:
Why not pandoc import filter.
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The above does not mean: "do not parser outside pandoc". There are reasons not to use pandoc. It means: Please explain why not. It helps others to choose.
Maybe this is not the answer for Asciidocr, but quite often the answer is "pandoc has an internal representation of what a document is. That representation is not as rich as many of the formats it supports."
Nothing comes close to Asciidoc(tor) for a complete documentation suite.
Neat project, nice to see more investment in the AsciiDoc ecosystem. I've shifted my focus to Typst, but I've long liked AsciiDoc as an authoring format.
Also TIL about HTMLBook, which looks like a nice subset of HTML for documents.