Your bank accounts will only reflect in the Banking section in QuickBooks Online (QBO) if they're connected through Online Banking (also known as Bank Feeds).
If they're already connected and still now showing, try signing into your QBO using a private browser (incognito). This will help us check if this is a browser-related (cache and cookies) issue.
Here's how:
Press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox).
Control + Option + P (Safari).
If everything looks good, return to your default browser and perform a clear cache to refresh the system. However, if the issue persists, try using other supported browsers.