I have 14k notes in a @Joplin store and have had no issues at all syncing via WebDAV and four devices using an aging Apache configuration. For reasons (stupidity comes to mind) I thought I'd modernise a bit and use Caddy. Since yesterday PM I'm seeing notes disappear, Joplin display errors that sync cannot continue b/c Failsafe, and whatnot. Re-installed Joplin twice on macOS and a fresh download all shows nothing. Now back to Apache, and all is back to working!