FYI, HS helpdesk informed us this work around option for making Outlook calendar work: = very clonky
Scheduling from contact/company/deal then syncing to a calendar is only supported on Google calendar at this time. This is my suggested process to my other customers who are also on Outlook:
-Schedule a meeting on Outlook (if the booking was made on the Meetings link, then simply accept the booking)
-In the contact/company/deal record, use “Log activity” then select the date and time based on your Outlook invite. Make sure to associate the contact/company/deal accordingly depending on which record type you’re logging the activity (e.g. if on deal record, then associate the activity with the appropriate contact). This becomes the “next activity” for the record.
-To track, create a Saved Filter view using the filter “Next Activity”. The most basic is “is known” or you can set a time period of your choice.