"Endpoint Manager" is just a rebranding of SCCM+Intune. Existing training on these products would be what you're looking for.
e.g.
- https://learn.microsoft.com/en-us/learn/certifications/courses/md-101t02
- https://learn.microsoft.com/en-us/learn/certifications/courses/20703-1
- https://learn.microsoft.com/en-us/learn/certifications/courses/browse/?terms=device
etc