I hope your day is going well. I'd be glad to provide info with correcting imported transactions in QuickBooks Online.
If those bank transactions that are already imported are in the For Review tab, you can delete multiple ones at once. The For Review tab is when your transactions need to be reviewed before they go into your register to be reconciled.
Here's how to delete/exclude transactions from the For Review tab:
Select the Banking tab in the left-hand menu.
Choose the bank to work with.
Click on the In QuickBooks tab.
Pick the transactions you want to exclude, then press Undo under the Action column.
Select the Batch Actions drop-down and choose to Exclude Selected.
Once you've followed the steps above and you're ready to import this year's transactions, you can download your bank statements from January until now to ensure you're only importing this year's transactions.
That should do it. Feel free to comment below if you have any other questions. Have a great rest of your day!