How do I delete all the duplicate matached and added transactions in the reconcile page?

Let me provide some information about handling duplicate transactions on the reconciliation page, mare.

The option to delete matches and add transactions can be done on the banking page. All transactions on the Reconcile page are the transactions that are added to your register from your Banking. It's best to undo and exclude them on the Banking since we're unable to do it when reconciling.

1. Go to the Banking tab and select the affected account.
2. From the Reviewed tab, locate the duplicate transaction and select Undo.
3. Select the For Review tab. Check the duplicate transaction and select Exclude Selected from the Batch Actions drop-down.

Additionally, I'm adding this article to see different guidelines that will help you fix any reconciliation errors: Learn the reconcile workflow in QuickBooks.

We also have reports about reconciliation if you need them in the future.

If there's anything else you need or if you have additional questions about managing your transactions, just drop a comment below. I'll be around to help you more. Take care.