Until Microsoft adds a straightforward way to delete addresses from the suggested accounts list, you can try the steps below to remove addresses from the Suggested accounts list.
Spellcheck and Microsoft Editor not working in new Outlook
How to fix the Microsoft Editor and spellcheck not working in new Outlook for Windows.
Gmail All Mail and Outlook’s Archive folder
Using Gmail's All Mail folder in new Outlook for Windows or classic Outlook for Windows. In the new Outlook, there is a folder named Archive and it appears to contain all of the messages in the All Mail folder in Gmail. Is new Outlook syncing All Mail?
"This account is not supported in Outlook" error message
New Outlook error: This account is not supported in Outlook due to the license provided by your work or school. Try to login with another account or go to Outlook on the web.
Automatically Open New Outlook when Windows boots
How to enable New Outlook for Windows to run automatically when you boot the computer.
Block External Content in New Outlook
How to block external content in the new Outlook that replaces Windows Mail app.
Save Messages in New Outlook
Learn how to save messages to the hard drive when using new Outlook app or Outlook on the web.
Reset the New Outlook Profile
When you switch on the new Outlook, it pulls accounts in from your Outlook desktop profile. I'll show you how to clear the profile and create a new profile.