There are some cases when you just want to patch a resource created by some other tool.

You deploy with kubectl directly, or your CD tool deploys the resource, and Crossplane composition patches it the first time it sees the resource, otherwise it should not create the resource, also it should not delete the resource.

What problem are you facing?

In k8s it's common that it is not a single tool managing a resource, but multiple ones manage certain aspects of it.

How could Crossplane help solve your problem?

The provider could work in a way where it only patches existing resources if they have been created, but otherwise just don't create the resource.

With the current management policies this is not possible really, An ObserveUpdate policy is missing.