A slow or loading bank connection indicates a slow internet connection or an issue in the bank's server. Try closing other programs on your computer that uses an internet connection. If nothing changes, you can log in to your bank's website to see if they have maintenance announcements. If non, you can do the basic browser troubleshooting steps.
Sign in to QuickBooks using a private or incognito window. This disables the browser extensions and stops the cache from saving your browsing history.
Google Chrome: Ctrl + Shift + N
MS Edge and Firefox: Ctrl + Shift + P
Safari: Command + Shift + N
If the feed will look fine, you can go back to your regular browser and clear its cache. If it's the same thing, please use other browsers to isolate the case.