I'm here to help you import your transactions, @Allmer.

Yes, you're correct. You can only import Accounts, Items, Customer and Vendor Lists using the QuickBooks Import Excel and CSV toolkit. I know another option you can use to get you going.

You can use the Intuit Interchange Format (.IIF) files to import your sales invoices, payment journals and general ledger journals. These data make it easier to transfer data to and from different platforms. This way, you'll be able to manage your company records better in QuickBooks.

Please note that QuickBooks doesn't offer technical support for the IIF import. If the said files came from a third-party app, you'll have to contact their support for further help.

Also, please make sure to back up your company files before importing your IIF's. This way, you can restore them anytime if ever run into problems.

Here's to import your data into QuickBooks Desktop (for QBDT 2020 and higher versions):

1. Open QBDT with login privileges (right-click on the QuickBooks icon, and then click Run as administrator).
2. Make sure QBDT is in Single-user mode.
3. Go to the File menu, and then choose Utilities.
4. Choose Import, and then IIF Files.
   
5. Select the IIF file you want to import, and then Open.
6. Click OK to continue.

For more information, please see this article: Import IIF into QBDT.

If you're using QBDT 2019 or later, please refer to this article for the steps: How to import IIF into QBDT.

After the successful import process, you can also customize your form templates. This way, you can personalize them based on your needs.

Feel free to mention me in the comment section if you have more file management concerns. I'm here to back you up always. Stay safe and have a great day!