Read ImageCatalog of Cloudnative pg #1630

I am using cloudnative pg as db operator. where we can create/ read/edit image catalog cluster.
In .net using this package I am able to successfully create image catalog.
but while reading it is in the form of plane string like structure. unable to convert it into key value pair like structure.

var config = KubernetesClientConfiguration.BuildDefaultConfig();
                var client = new Kubernetes(config);

                var imageCatalog = await client.GetNamespacedCustomObjectAsync(
                    appSetupK8SConfig.HelmChartGroup,
                    appSetupK8SConfig.HelmChartVersion,
                    appSetupK8SConfig.Namespace,
                    GlobalConstants.ImageCatalogPlural,
                    appSetupK8SConfig.ImageCatalogName
                    );

and imageCayalog is like this

ValueKind = Object : "{"apiVersion":"postgresql.cnpg.io/v1","kind":"ImageCatalog","metadata":{"annotations":{"kubectl.kubernetes.io/last-applied-configuration":"{"apiVersion":"postgresql.cnpg.io/v1","kind":"ImageCatalog","metadata":{"annotations":{},"name":"test-image-s-postgresql","namespace":"ingress-basic"},"spec":{"images":[{"image":"demo.azurecr.io/test-db-devl:17.2","major":17}]}}\n"},"creationTimestamp":"2025-05-16T06:20:44Z","generation":2,"labels":{"k8slens-edit-resource-version":"v1"},"managedFields":[{"apiVersion":"postgresql.cnpg.io/v1","fieldsType":"FieldsV1","fieldsV1":{"f:metadata":{"f:annotations":{".":{},"f:kubectl.kubernetes.io/last-applied-configuration":{}}},"f:spec":{}},"manager":"kubectl-client-side-apply","operation":"Update","time":"2025-05-16T06:20:44Z"},{"apiVersion":"postgresql.cnpg.io/v1","fieldsType":"FieldsV1","fieldsV1":{"f:metadata":{"f:labels":{".":{},"f:k8slens-edit-resource-version":{}}},"f:spec":{"f:images":{}}},"manager":"...

how can i convert this plain string like json into actual json or object so i can easily edit it.

i want to use ReplaceNamespacedCustomObjectAsync to edit catalog image.