Hello @Troops !
Welcome to Microsoft QnA!
Here is the link with all the answers !
But please notice the version of Defender is Plan 2 ! What is you License ?
When you see Microsoft Endpoint Configuration Managment it is Intune , so yes it is very easy to Onboard devices to Defender via Intune and it is a prefered method!
Please feel free to ask more details , or mark this answer as Accepted !
Thank you in advance!