Yes, you can perform manual reconciliation in QuickBooks Online (QBO), elite13.
Since you don't want to link your bank account, you can manually enter or upload transactions. This lets you track them without linking the account.
I'll guide you on how you can reconcile your account:
- Navigate to the Gear icon, choose Reconcile, and then Get started.

- From the Account dropdown list, select the account you want to reconcile. Ensure it's the same one on your statement.
- Confirm that the Beginning balance in QuickBooks matches your statement.
- Input the Ending balance and ending date from your statement.
- If your account isn’t connected to online banking, enter any service charges or interest earned during the period.
- If visible, check the Last statement ending date to ensure your current statement starts the next day.
- Select Start reconciling to compare transactions one by one.
- Once you have reviewed all transactions and the difference between your statement and QuickBooks is $0.00, click Finish now.

I'll add this article for additional reference: Reconcile an account in QuickBooks Online.
Feel free to reply to this thread if you need further assistance with bank transaction management. I’m here to help.