How are things, Dominika? I'm here to help you out with your concern!
When you access the Reconciliation page, the current beginning balance that shows up is the amount they used for the ending balance in the previous reconciliation.

Initially, the Cleared balance will match your beginning balance (please refer to the screenshot above). However, it will change once you select a transaction/s.

Considering that no transactions are currently displayed for the remaining balance, we can double-check the bank statement and verify that you are reconciling the correct month and appropriate transactions.
In addition to that, I suggest reviewing the Discrepancy report to identify any modifications that may impact the reconciled transactions. If that's the case, you may undo and reconcile them again. For more details, you can refer to this article: Fix issues for accounts you've reconciled in the past in QuickBooks Online.
If you have any further concerns or questions, please don't hesitate to reach out. I'm here to assist you and will be available to help. Take care and stay safe!