Thanks for bringing your concern to me, georgmuller. You don't miss anything.
Let me share some insights about it.
QuickBooks Desktop and QuickBooks Online are two different products. They have different features and offers to customers. In QuickBooks Desktop, you can add more companies with the same subscription or license number.
While QuickBooks Online, you'll need to have a subscription per company. Each company file is a separate paid subscription, but you log in with the same credentials. Once you have multiple QBO companies, you can simply switch from one company to another quickly. See this how do I switch companies article for more information.
Also, I'd like to share with you this helpful article for reference about tasks related to your company and accounts: Help Articles for QuickBooks Online.
Post your QuickBooks concerns anytime. I'm here to make sure you'll be given the correct details of your queries. Stay safe and have a good one, georgmuller.