Lorenzo wrote an article about how to use iA Writer for macOS as your Zettelkasten note archive. Apparently, iA Writer has a sufficiently quick search for large archives (10,000 notes big, in fact), which surprises me.
As a native macOS app, you can use iA Writer to sync with Dropbox, iCloud, and other folder-based sync services and either use their mobile or Windows counterparts, or whatever else you like. No boxing-in.
Have a look at Lorenzo’s review for all the juicy details. Great work!