There are those that have well defined extension points (e.g. TeX, rst), and those that are ad-hoc, of which the best example is markdown. TeX, via packages and wrappers, can do practically anything. rst has directives (blocks) and interpreted text (inline) which can also effectively do anything (along with substitution references which are more macro-like). Specific "interpreters" (for lack of a better term) which you link to naturally have specific features by default (and some are more extensible than others e.g. pandoc which when writing out LaTeX lets you embed LaTeX in the markdown, so "markdown" in this case is turing complete).

I think if you define "better" as having well-defined extensibility to enable multiple implementations (i.e. not ad-hoc things pandoc lets you do), then rst (which can be transformed into XML as per https://docutils.sourceforge.io/docs/ref/doctree.html) would be "better" than markdown.