What are some resources and tools for measuring customer insights & KPIs? I'd like to track customer churn, op costs & revenue.

For customer insights, I can recommend using Google Analytics 360 Suite. For KPI’s Salesforce is a powerful tool. Also, you can combine both of the these with Segment tool to generate meaningful insights and dashboards to visualize the data
You can read more about it here: https://segment.com/

Another solution is to start from the company’s operational systems, i.e. those used to track customers and orders as well as costs. The present state of the art is to extract the relevant data of these into data warehouses. The next step would then be to use data preparation and B.I. tools to display and analyze the data through e.g. Tableau Prep and Tableau Proper (many more tools by different suppliers exist).