NotePlan (https://noteplan.co) stores everything in Markdown files with a directory structure mirroring that created in the UI
The more you use it the more it will reveal its power and flexibility
It is one of the only products I know of that is fully committed to a being a bunch of markdown files as data while also using lots of database smarts.
NotePlan makes a point of interop with Obsidian
https://help.noteplan.co/article/61-use-noteplan-with-obsidi...
Yes, NotePlan is a paid subscription. But they have honestly figured out how to make you pay for their experience and not locking up your data.
While it works best on macOS, iPhone and iPad, their recently released Web App is making great strides in feature parity.