Hi Nick,
Very interesting idea!
Here's one possible approach, but there may be some hurdles you'd have to work through:
You could use Power Automate and create a flow that will trigger based on Business Central record inserts or changes, and then create O365 calendar events.
Here's a screen shot of a quick sample flow I created. My BC sandbox tenant doesn't have Service available, but you could give it a try and see if any Service tables are exposed in Power Automate. If not, you might be able to create a custom connector using a BC API--assuming there is an API for Service.
It appears that the number of BC connectors (all in Preview) are limited, and the data exposed by the preview connectors is also pretty limited. So I'm guessing you may need to create custom connectors that can retrieve the data you need from BC.
