It's great to see you managing two companies in QuickBooks Online (QBO). You're correct that you'll have to get a new QBO account for the second company, especially when both have separate company data.
Also, you can associate them with your existing company using the same login credentials to give you easy access by switching QBO accounts.
Feel free to comment if you need more assistance creating a new company. I'm always here to lend a hand to your business's continuous success. Have a nice day!