Let's make sure that you've successfully connect your bank into QuickBooks Online so that it will show in the Banking menu. Please check this out:
On the Dashboard under Bank Accounts, click Connect account.
Enter your bank or URL in the search field.
Select Continue.
Choose the account you want to connect with.
From the drop-down menu, select the Account Type.
Choose the date range for the download.
Tap Connect.
If you've already connected it but still doesn't show on your Banking page, we can try logging in to your account using a private browser to check if this has something to do with your browser's cache. Here are some keyboard shortcuts:
Ctrl + Shift + N for Google Chrome
Ctrl + Shift + P for Firefox
Control + Option +P if you're using Safari
If it works, let's go back to your default browser and clear its cache. Excessive older data can potentially cause unusual behaviors in QuickBooks. Otherwise, we can use other supported browsers.
I also recommend checking out these articles about uploading your bank transactions manually and on how to categorize them: