curl --request DELETE \
  --url https://api.example.com/v1/preview/models/{model_id}/checkpoints \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "steps": [
    123
  ]
}
'

{
  "deleted_count": 123,
  "not_found_steps": [
    123
  ]
}