Buhata writes to your device first and syncs after. That's the opposite of most apps, and it's why the thing keeps working in a basement parking garage.
Working with no connection
Everything functions. Adding entries, ticking tasks, the calendar, the lists. Nothing waits on a request.
When a connection comes back, changes go up on their own. The dot at the bottom of the sidebar tells you where things stand, and it shows a time when it last succeeded.
What if I used it before signing in?
That work belongs to you, so signing in brings it with you rather than replacing it. Anything you created on the device gets carried up into the account.
Where both hold a record of the same thing, the account's version wins. Nothing you wrote gets quietly overwritten by a device holding an older copy.
Two devices, two answers
The account is the source of truth. A device that's been offline takes its copy from the account when it reconnects, and anything it created that the account has never seen gets carried up.
Moving to a new phone
Install Buhata, sign in, wait for the sync dot to show a time. Nothing needs exporting first.
If the old phone still has things it never managed to send, open it once with a connection before you wipe it.
When something looks wrong
If the dot never settles, sign out and back in on the device that seems behind. It'll take a fresh copy from the account.