Reports

the API spec of the Azure DevOps - Approvals And Checks - Check Configurations is here.

A sample payload looks like this. Seems like your approver object is slightly different.

POST https://dev.azure.com/{organization}/{project}/_apis/pipelines/checks/configurations?api-version=7.1-preview.1

{
  "settings": {
    "approvers": [
      {
        "displayName": null,
        "id": "3b3db741-9d03-4e32-a7c0-6c3dfc2013c1"
      }
    ],
    "executionOrder": "anyOrder",
    "minRequiredApprovers": 0,
    "instructions": "Instructions",
    "blockedApprovers": []
  },
  "timeout": 43200,
  "type": {
    "id": "8c6f20a7-a545-4486-9777-f762fafe0d4d",
    "name": "Approval"
  },
  "resource": {
    "type": "queue",
    "id": "1",
    "name": "Default"
  }
}

refer to this link for all field specs.
https://learn.microsoft.com/en-us/rest/api/azure/devops/approvalsandchecks/check-configurations/add?view=azure-devops-rest-7.1&tabs=HTTP

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