I can share information with you to avoid multiple deposits in QuickBooks Online.
When recording payment in QuickBooks Online, the default account will be Undeposited Fund. This serves as a holding account for customer payment. You can now create a bank deposit to move the funds from Undeposited Funds to your bank account as it hits your bank. If you have downloaded a bank transaction, choose Match instead of Add to avoid duplicates.
Duplicate downloaded transactions from your financial institution may appear sometimes. To ensure that it does not show in the connected bank, you must remove it from the For review tab on the banking page.
Here's how:
Go to the Banking or Transaction menu.
Select the Bank account you're working on.
In the For review tab, click the duplicate transaction.
Choose Exclude, then go to the Excluded tab to delete it.