Hello there, mm_mm.

Using a third-party app is a great idea to transfer those data to your new QuickBooks account.

I suggest that you contact the third-app support to help you further in exporting those transactions.

You can also checkout this article to learn how to export and use the reports and list that you have in the old QuickBooks Online account to help you review all transactions exported: Export reports, lists, and other data from QuickBooks Online.

Click the reply button below for follow-up questions about it. I'm always here to help. Have a nice week!