I can provide details about accessing a new bank account in QuickBooks Online (QBO).
All the bank accounts you can see in the Banking menu in QBO are connected to Online Banking. Since you don't want to link the new one, you can go to the Chart of Accounts (COA) and add it from there instead.
Here's how to do it:
In QBO, go to the Gear (Settings) icon at the top right.
Select Chart of Accounts.
Hit New.
Choose the account type.
Enter a name and other necessary information.
Tick Save and Close.
For more information about managing online banking and COA in QBO, consider checking out these articles: