I'm glad you find your way here in the Community, Kefro.

You'll want to exclude the previously downloaded transactions and redownload those with the correct dates. The Exclude Selected option can be found under Batch actions from your Banking tab. Let me share the steps on how to do it below:
 

1. Go to the Banking menu on the left panel.
2. Choose the Banking tab.
3. Check the box beside the transactions you want to exclude.
4. Click the Batch actions drop-down and choose to Exclude Selected.

To know more about the process of excluding downloaded transactions in QBO, feel free to visit this article: Exclude a bank transaction you downloaded into QuickBooks Online.

Once done, you can manually add the transactions with the correct dates. For instructions on how to do this, check out this article: Manually upload transactions into QuickBooks Online.

Drop me a reply if you have any follow-up questions about excluding transactions. I'm always happy to help.