Joining the thread to share information about your account balance, @cetanorak.

Each credit card subaccounts balance will result in the total balance of the parent account. Based on how you describe them, each subaccount downloads the transactions by income and expenses respectively.

You don't have to worry, each subaccount balance is correct once the parent account has been reconciled based on the transaction on your statement. Here's an article to read more: The Bank and Credit Card Subaccount Setup.

I also suggest contacting your accountant for guidance in understanding each account balance along with working the reconciliation. Use the link to find someone you want to work with: The QuickBooks Certified ProAdvisor.

I'm adding this article with topics to use while working with your credit card account and transaction reconciliation: Banking in QuickBooks Online.

Feel free to let me know if you have other concerns about managing your account balances and transactions. You can drop a comment below, and I'll gladly help. Take care, and I wish you continued success!