Same problem here. When going to the Sync Email tab I get Unable to load these settings.
My problem, is that my Gmail is still syncing to my Outlook account. I have no way to stop it, no way to remove it.
Not cool when someone is pulling email from an account when you don't want them to, I wonder if that is a privacy issue or something.
For that you can change your password on your GMail account which will break the Outlook syncing it. But then it sounds like from other people you might get constant warnings about Outlook not being able to connect to your GMail.
So then for that you probably have to create a new Outlook email address, change your Microsoft Account to that, and delete the old one. And that's only if nobody uses your old @outlook.com email and you can part with it.
https://www.makeuseof.com/tag/how-to-delete-outlook-hotmail-account/
So once again I have absolutely no problem saying the entire Outlook.com team and management are a complete bunch of IDIOTS and it has only been getting worse I would say the last 5 years or so. It started when they forced the old Hotmail/Outlook web users to the new Outlook.com which has never been as good as the old Hotmail web interface as far as reliability.
Hopefully the Monarch/One Outlook that is in the works will finally work as it should and maybe if we are lucky work half as good as the old Win32 Desktop Outlook did a decade ago.