Whether you buildyour QB file starting from scratch or using an Excel spreadsheet, the issue is the same when you try to start books after the company has already commenced operations. You will always have one or more accounts that have a starting balance that pre-dates any transactions you will later enter.
Let's say you have a very simple company with just 4 accounts: Checking, Owner's Equity, Machines, and Income. The company has a starting checking account balance of $100.
Per the rules of accounting, your books must always be in balance using the basic formula Assets = Liabilities plus Equity. (A=L+E)
If you have $100 in the checking account, and there are no liability accounts and the other two accounts have no entires, then the Equity account MUST also be $100..
If instead, you borrowed the money and took out a loan for $100 to start the company and put the $100 into the checking account, the opening balance of $100 in the checking account would have to be offset by a $100 Liability (Loans), and nothing would be in the equity account. Still A=L+E
Because you cannot possibly know where all the corresponding balances are when you set up a company that is already operating, such as yours, you cannot simply offset the checking account with a little bitty entry to each of potentially hundreds of accounts on your books.
Instead, by posting the opposite entry of the opening balance in the checking account against the generic Owner's Equity (OE) account, you can use the OE account, either using General Journal entries or direct entries to post the correct opening balances to ALL of your accounts. This sort of acts as a hub to make sure the accounts and the formula is always in balance. Ultimstrly, when you have finished entering all your opening account balances, the Owner's Equity account will reflect only the true OE amount.
So, in other words, you cannot get around calling the opening balance in Quickbooks anything BUT Owner's Equity. unless you manually allocate all the splits to the other accounts, which is usually impossible.