When it comes to setting up a Business Event BE endpoint: D365FO just sends a basic data contract (“payload”) via POST method.
So, in fact we can use Microsoft Power Automate endpoint type to interact with your eventual MuleSoft HTTP listener.
A simple app (a flow) in MuleSoft Design Center consisting of two steps: HTTP listener and Logger.
This basic BE data contract info to add a new type:
{"TestField":"","BusinessEventId":"","ControlNumber":0,"EventId":"","EventTime":"/Date(-2208988800000)/","MajorVersion":0,"MinorVersion":0}
For you particular case you can use pre-generated scheme for your new Business Event.