The bank balance is your bank's actual balance from the last bank feed update. Thus, it'll total the amount of all the transactions made from your bank.
If you're referring to bank sub-accounts, you can connect each of them in your QuickBooks Online (QBO) to get their bank balance. However, not all of the bank allows connecting sub-accounts. Thus, the transactions will go directly to the parent account.
However, if you're referring to the category accounts, we can't show each balance of them.