You want to delete multiple controllers from the cloud console at the same time, but it will only let you delete one controller at a time.
Cloud Workload Protection for Storage
Currently, CWP Console doesn't support deletion of multiple controllers. Multiple deletion of controllers is not supported via REST API as well. It was a design decision not to support deletion of multiple controllers.
This is because, as part of deletion of controller following tasks are performed:
Currently, you must delete them one at a time from the console.