The GitHub discussion reminds me of all the different approaches Dendron could take, and how it's a difficult thing to approach. The discussion ends up actually bringing up something I didn't know of: the generic directives proposal. Looks like remark already has a plugin via

remark-directive

that could maybe make approach to admonitions easier, and could potentially be a path for Dendron in other ways

this continues on theme of dendron being a "pandoc for everything" - your notes, in dendron, should be transferable to any destination