What CSMs need is similar to what Customers need in their CSMs - they need support, they need coaching and guidance, they need to be challenged, they need tools and training, they need someone advocating for their success. In short, they need what Brett Andersen of Degreed calls an Employee Success Manager (ESM).
While CS metrics have somewhat started to standardize, cost to retain is not often mentioned in the mix. Bruce Cleveland of Wildcat Venture Partners talk about why it's important when measuring the health of your SaaS business
A lot of Customer Success professionals are in their first CS role, having come from Support, Sales, and many other departments with no formal training. Clint Fontanella of Hubspot gives us a list of different training options for yourself or your team.