The link for the guide you mentioned doesn’t have any information on the page.
All of the settings in WP Mail are correct. I have used it where I work for years. The 365 email address is a paid for email address so I wouldn’t be under a trial tenant. I tried the delist yesterday and the IP wasn’t listed. Would the low reputation IP address still apply if I can send and receive email fine outside of WordPress and the WP Mail plugin?
Is there any other way to contact Microsoft besides their forum? I have the 365 Email Essentials plan with Godaddy. I don’t believe that is a business plan so I can’t get phone support. The only option was to post on a forum.