Depends on how deep you want to go. The pioneering work in this field is the "The multiscale coarse-graining method." series of papers kicked off by Noid. Who is still a person to pay attention to in this field.

I also believe the work of Frank Noe is someone to watch for in the ML potential space for proteins.

I'm also always happy to talk about CG.

I am currently working on CG potentials. Can really recommend the basics from Gregory A. Voth.