Congrats on your first post in the Community. It's good you're making sure your transaction are correct in QB. I'd be glad to show you how to delete transactions you've just imported to QBO.
To do this, follow the steps below:
From the Banking screen select the relevant bank, then select the For Review tab
Tick the transactions you want to exclude, then select Batch actions and then Exclude selected
Select the Excluded tab
Tick the transactions you want to Delete
Select Batch actions
Select Delete
A message will pop up asking Are you sure? These transactions will not be recoverable