The only HTTP method supported is POST. This is not a SCIM (bulk) endpoint, although it is modeled after SCIM in many ways. The feature you are referring to is the "Inbound Provisioning API". Some documentation links are below.
https://learn.microsoft.com/en-us/entra/identity/app-provisioning/inbound-provisioning-api-concepts
https://learn.microsoft.com/en-us/entra/identity/app-provisioning/inbound-provisioning-api-faqs
The last link in that set is the technical API documentation. Only POST is supported, and it does not behave as a SCIM POST does, but more along the lines of a flat file/CSV upload into a queue to be processed by the provisioning service. You can configure the inbound API provisioning job to disable a user but it cannot delete them.