Hello useranibroek,
Welcome to Community! You are correct! When signing into QuickBooks Online, you'll see a list of all accounts associated with your email address, based on your user role. Client accounts will be visible under your Accounting firm, while any other accounts you've been added to as a Company Admin, or other user type, will appear under QuickBooks Online companies.
Feel free to reach back out with other questions. We would be glad to help!