Via the Cloudflare UI (see image), it's possible to create an Origin CA certificate without providing a private key and CSR. Cloudflare will generate this for you.
I've tried to find the corresponding approach using the Cloudflare API, but it seems I have to provide a self generated key and CSR when doing that.
Does anyone know if it should be possible to auto generate via the API (or Terraform/Pulumi) as well?
https://developers.cloudflare.com/api/operations/origin-ca-create-certificate#requests
I guess I found the answer to my question in the Pulumi provider documentation. They are creating a key and certificate signing request before using them when calling cloudflare.
https://www.pulumi.com/registry/packages/cloudflare/api-docs/origincacertificate/