Weird Calendar sync issue - can anyone help?

[MightNotBeThere]

Just switched from an Essential to a company mandated S10. Everything seems to be working fine, with the exception of Calendar, or more accurately, 2 out of 3.

I installed Outlook for Android to see if it would work, synching correctly to my from Exchange account. All good, emails & calendar working fine.

What I really want is for my Blackberry Hub & Blackberry Calendar to work properly. When the BB Calendar syncs, so does the Google Calendar.

Here's where it gets weird. When I add a new item to my desktop Outlook calendar, it is synced almost instantly to the calendars on the phone & vice versa. Great.

The problem is that the existing 500+ calendar entries on my desktop do not sync at all, only new items, or changed items sync to BB and Google Calendars. The Outlook one works fine and has all entries in it, old, and newly added or changed.

I downloaded 3 other calendars to see if they would work - no, so I deleted them.

Obviously, I've set something incorrectly but I have no idea what. I've spent half the day Googling this and trying various solutions without success.

Any suggestions please, anyone?

 

[Rukbat]

Calendar sync is on changes, not on static data.

 

[MightNotBeThere]

I have to doubt that as the calendar part of Outlook for Android syncs perfectly, old entries, new, adjusted, whatever - everything where it is supposed to be.

But nothing other than new entries in Google Calendar or the Blackberry Calendar which is the one I really want to work.