CalDAV calendar integration

I am currently working with the brand that represents the Zimbra solution here in Brazil. That said, unfortunately we cannot use standard providers that have native integration for the following reasons:
- 1 Ethical issue
- 2 You trust the product you sell and do not see the need, nor as stated in reason 1, to purchase a standard provider just to integrate your email and meeting calendar to use the account’s scheduling solutions.
As a result, he has an emergency situation in his team’s sales and scheduling processes without proper monitoring. In addition, of course, to all other Zimbra customers who currently have a Hubspot account and cannot connect and integrate their calendar control synchronized with their provider.

Please consider this subscription as a priority because today we have several companies in Brazil that are not Google or Microsoft and are limited in the tool.
This specific customer is even thinking about canceling the account due to this problem, so if there is any other solution that could help, I am here to listen. Furthermore, I hope that the product area addresses this subscription as a priority as soon as possible.