Thank you for raising this issue. The "Auto sync on modify" is designed so that beorg will still sync when it goes into the background, or returns to the foreground, but won't sync each time you modify a file. Maybe an additional setting (possibly with some rewording) is required to make syncing completely under the user's control.
I'll investigate why beorg is taking so long to notice that it can't access your WebDAV server.
beorg-user
Hello!
I've noticed an issue that on opening the beorg app, it tries to sync, but the server is not available at that moment, and then it takes a (too) long time till beorg cancels the sync and allows me to add new entries / use the app for editing (which implies saving stuff) purposes.
Setup: