Hello there, @WyrtWicce.

Thank you for choosing QuickBooks Online.

 I can share insight about importing files to QBO if you're using a credit card account.  Transactions may appear in reverse in CSV files for credit card accounts.

Choose a credit card account when uploading this type of file. This ensures that the transactions import correctly.

I added this article if you may want to know common errors in importing CSV files.

Additionally, have this article to fix bank upload errors in QuickBooks Online.

After downloading the bank transaction successfully, you can categorize and match them. Here’s how:

1. Go to the Banking section and select Banking.

2. Under For Review, tick the box for the account you want to categorize.
3.Once done, all the categorized items will reflect in the reconciling items.

Furthermore, learn how to match bank transactions in QuickBooks Online.

If you need more assistance about uploading a file, just hit reply. I am willing to help you always. Take care.