k8s CRD definition: 4 mutually exclusive optional fields

I have created a CRD for a resource and currently unable to make them mutually exclusive and optional at the same time:

optionOne:
  type: string
optionTwo:
  type: string
optionThree:
  type: string
optionFour:
  type: string

How to combine exclusitivity and optionality of these fields?

I tried using

oneOf:
- not:
    required: ["optionOne"]

But it didn't work.

I used Rust and kube-derive to define a FourOption type that takes an optional oneOf value. It generated the following CRD:

fouroption.crd.yaml:

apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: fouroptions.example.com
spec:
  group: example.com
  names:
    categories: []
    kind: FourOption
    plural: fouroptions
    shortNames: []
    singular: fouroption
  scope: Namespaced
  versions:
  - additionalPrinterColumns: []
    name: v1alpha1
    schema:
      openAPIV3Schema:
        description: Stackoverflow 78523396
        properties:
          spec:
            properties:
              foo:
                nullable: true
                oneOf:
                - required:
                  - option_one
                - required:
                  - option_two
                - required:
                  - option_three
                - required:
                  - option_four
                properties:
                  option_four:
                    type: string
                  option_one:
                    type: string
                  option_three:
                    type: string
                  option_two:
                    type: string
                type: object
            type: object
        required:
        - spec
        title: FourOption
        type: object
    served: true
    storage: true
    subresources: {}

NAMESPACE="78523396"
kubectl create namespace ${NAMESPACE}

kubectl apply --filename=./fouroption.crd.yaml

customresourcedefinition.apiextensions.k8s.io/fouroptions.example.com configured

Then I tested with none; oneof; and multiple:

kind: List
apiVersion: v1
metadata:
items:
# Expect: succeed
- kind: FourOption
  apiVersion: example.com/v1alpha1
  metadata:
    name: none
  spec:
    foo: null
# Expect: succeed
- kind: FourOption
  apiVersion: example.com/v1alpha1
  metadata:
    name: option-two
  spec:
    foo:
      option_two: Hello Freddie
# Expect: fail
- kind: FourOption
  apiVersion: example.com/v1alpha1
  metadata:
    name: multiple
  spec:
    foo:
      option_two: Hello Freddie
      option_four: Hello Freddie

Yields:

fouroption.example.com/none created
fouroption.example.com/option-two created
The FourOption "multiple" is invalid: <nil>: Invalid value: "": "spec.foo" must validate one and only one schema (oneOf). Found 2 valid alternatives