I'll share insight on your query about the parent account and its sub-accounts in QuickBooks Online (QBO).
It appears you record your credit card transactions by hand. You can consider connecting these accounts to your QBO company, if available. Please be advised, you can either connect the parent account or its sub-accounts. It depends on where your bank posts the transactions.
More details on this subject are in this article: About bank or credit card subaccount setup.
I'll share this article for your reference as well: Record your payments to credit cards. It has a list of options on how to record credit card payments in QBO, such as checks, or bank transfers.
Feel free to post a comment if you have other questions, and I'll be sure to take care of it.