My banking is no longer connected / showing transactions in QB..

I can share some information, @rodr1. The categorized and reconciled transactions will remain in the bank register in QuickBooks Online (QBO). 

Linked transactions will be saved in the register from the Banking page even though the account was disconnected. It's for documentation purposes as it will affect other books linked to the categorized transactions.

However, if you want to delete it, you can click on the transactions from the bank register, and do the action. I've added a screenshot for your reference:

For more details, you can check this reference: Categorize and match online bank transactions in QuickBooks Online. It also contains tips on how to manage bank transactions in QBO.

You may see this article helpful in the future whenever you're ready to assess your business accounts: Reconcile an account in QuickBooks Online.
 

 If you have any other questions, please reach back out in the comment section. I'd be happy to help. Take care!