It covers many types of infrastructure outside of K8s. In the sense that you can use it to templatize infrastructure and inject many configs, it can work like helm. You can also use it in many other ways as well- creating your own classes, helper libraries, ternary operators, and all of the comforts of a general purpose language (often with a debugger).

Pulumi can deploy existing helm charts- just create a Helm resource, tell it where to look for the helm file, and it will deploy it and own its state moving forward.