Closing a business. Reconciled my bank balance with account activity in QBs. Even though everything is reconciled, discrepancy in bank vs QBs balance remain. What to do?

reconciled only means you that you matched transactions listed in QB against those listed by the bank.  There can be transactions in QB that never cleared the bank, you have to research them and find them and decided what you will do about them.

Hello there, @angelicasteinmei.
 

Bank Balance is the running balance of your bank as of the last updated transaction. This pulled up automatically from your Bank while the QuickBooks Balance is the balance of your Bank register within QuickBook Online.
 

You may need to check the transactions that are not matched in your Banking page as this will cause the difference. Also, the Opening Balance will cause this problem, if it's not correct.
 

To get this fix, review the opening balance entry in QuickBooks and compare the balance to your bank statement.
 

If the opening balance in QuickBooks doesn't match your bank records, edit it:
 

1. Select the opening balance entry to expand the view.
2. In the Deposit column, edit the balance so it matches your bank records.
3. Select Save. Then select Yes if QuickBooks asks you to confirm.

After you make changes, the Total Discrepancy Difference on the report should be $0.00. Your beginning balance in QuickBooks should match the beginning balance on your bank statement.
 

You can resume reconciling to update everything that has changes. You can refer this article to for detailed steps and further information about Fix opening balance issues in QuickBooks Online.
 

Keep me posted if you need anything else. I’m always here ready to help.