There are just a few idiosyncracies I couldn't get past- the most critical being that it doesn't actually use Markdown, just a syntax which is similar to Markdown
I hate markdown.
Far too much incompatibility between apps; far too many variations.
It's a babel not a language.
And still many things it doesn't do.
Far too many bits of HTML added to supplement the last. But the choices are often idiosyncratic.
I like your certainty that there is only one true markdown but I'm not a believer at all.
Like the early days of PCs when there were thousands of models all claiming to be IBM compatible and reviewers had to rate how compatible they were. And we'd probably still be there if Microsoft hadn't 'saved' the day by making MS DOS the standard.
Obsidian does use the wiki [[ but equally accepts the md (). This feels like a developing standard.