Not a kubernetes expert, but my understanding is that that operators are regular programs that run in a kubernetes container and interact with the kubernetes API to launch/manage other containers and custom kubernetes resources.
An operator (or its custom resource) can be configured by Kubernetes YAML/API and its upto the creator of the operator to specify the kind of configuration. If the operator creator did not specify options to set cpu/memory limits on the pods managed by the operator, then you can't do anything. You have to add that feature into the operator and then make a pull request and wait for it to be upstreamed.
Or fork it instead. Same thing for helm charts (except forking and patching them is easier than forking an operator).
An operator (or its custom resource) can be configured by Kubernetes YAML/API and its upto the creator of the operator to specify the kind of configuration. If the operator creator did not specify options to set cpu/memory limits on the pods managed by the operator, then you can't do anything. You have to add that feature into the operator and then make a pull request and wait for it to be upstreamed.
Or fork it instead. Same thing for helm charts (except forking and patching them is easier than forking an operator).