It seems like there are two ways of using Copado: either install the managed package in a Salesforce environment or use the online Essentials tool. Is there a sync or connection between these two solutions?

Correct, there is no connection between Copado Essentials and Copado CI/CD. Essentials is a web-based application designed to simplify Salesforce metadata deployment. Copado CI/CD is a complete DevOps solution built on the Salesforce platform.

As your DevOps process evolves and your team grows, you may want to consider upgrading from Essentials to Copado CI/CD. Check out this eBook called Copado Platform Options to learn more. If you do decide to transition from Essentials to Copado CI/CD you can continue to use your Git repository and planning tools like Jira.