Using Outlook for Android in business environments for email and scheduling
I have the same situation and experienced exactly the same with Android Outlook POP3/IMAP/SMTP account settings issue and the approach of support contacts what you wrote, still with the latest version too, which is currently 4.2123.0.
Galaxy own email app works well with different accounts, but its calendar has syncing problems.
Several calendar entries aren't syncing and impossible to force the correct syncing of these entries. And this calendar replication/syncing issue persists in several Calendar apps, also in Google calendar. So it seems the base of this calendar syncing issue is an Android OS level bug.
Only the Outlook Calendar is syncing correctly (and the OneCalendar too, which also worked well on Windows 10 mobiles).