It’s actually MDSVEX (the svelte version of MDX), we are weighing out a move to markdoc.
You could use [`data.mrr`](https://evidence.dev/md/value) or any other internal DSL you can come up with.
Another thing you could do is just decide against MD(SVE)X the format and keep the style and transform inline codeblocks that match. (MRR grew by `<Value data={data.mrr}>` yesterday.)
That you said Markdown to me says you aren't on sold on using an incompatible syntax.