I seem to be having issues with setting up a couple of my email accounts as they don’t appear in my list of accounts
If you are using a Free License, you can only have 2 email accounts. Any others you setup will not be displayed in the side-bar. Maybe that is the issue?
Another possibility is that if the account has not been setup correctly, or there was an error during the setup, the account will not be displayed in the side-bar. If there are no errors, the account will display as soon as the first sync begins.
You can also look in Menu > Tools > Operations, in the Log tab, and see if there are any errors.