Having the ability for a main board to sync live with the duplicate/mirrored board would be tremendously helpful. This should include parent & sub-item syncing.
For ex: Any time an item or subitem is created, updated, or deleted, it should also get happen on the duplicated/mirrored board.
What are you trying to achieve
Avoid missing updates from the internal (main) board to the shareable board, making sure they’re always in sync without manual updates or automations needed.
If you’re open to using marketplace apps, I’d definitely recommend looking into Same Item Multiple Boards app. It allows you to mirror the same item across multiple boards while keeping everything fully synced - including item creation, updates, and even deletions. So, any change made on one board automatically reflects everywhere else.
We use it ourselves, and it’s been a really powerful and reliable solution.