If you're only on Apple devices, Bear notes is an extremely consistent, scalable, and stable alternative.

In terms of polish, it's comparable to Craft, but with only the feature-set of Markdown. A few things are missing such as tables and backlinks.

It uses an SQL database for performance reasons, but export to Obsidian is possible within minutes. Indeed, while other file-based alternatives such as NotePlan fail to deal with my 5000+ notes, including images and attachments, Bear is still as smooth as on day one.

Just don't expect new features any time soon. The Bear team has been working on the next version for years, with no end in sight.