This is actually the reason I don't use Obsidian. It's built on markdown, but it is not markdown. Things may be different now, but when I gave up on Obsidian, there was no general purpose exporter - you either use their editor or you lose much of the useful information in your notes. This would not by itself be a big problem except for the fact that Obsidian is a standard piece of proprietary software. It genuinely solves nothing in regard to future proofing.