In the 1.14 release, we have some upstream features selected by PM to test. 

These two features are placed behind feature gates:
- https://issues.redhat.com/browse/CM-292
- https://issues.redhat.com/browse/CM-293

To use these fields, the feature gates "LiteralCertificateSubject" and "OtherNames" needs to be enabled on the cert-manager controller and/or webhook.

cert-manager operator v1.14.0

Tried twice, both occurred

$ oc patch certmanager.operator cluster --type=merge -p="
spec:
  controllerConfig:
    overrideArgs:
      - '--feature-gates=LiteralCertificateSubject=true'
  webhookConfig:
    overrideArgs:
      - '--feature-gates=LiteralCertificateSubject=true' 
" 

Error from server (NotAcceptable): error when creating "local/manifest/CM-292/cert.yaml": admission webhook "webhook.cert-manager.io" denied the request: spec.literalSubject: Forbidden: Feature gate LiteralCertificateSubject must be enabled on both webhook and controller to use the alpha `literalSubject` field  

$ oc get po -n cert-manager cert-manager-6db6ffb49c-dbl7f -o yaml
...
spec:
  containers:
  - args:
    - --acme-http01-solver-image=registry.redhat.io/cert-manager/jetstack-cert-manager-acmesolver-rhel9@sha256:...
    - --cluster-resource-namespace=$(POD_NAMESPACE)
    - --leader-election-namespace=kube-system
    - --max-concurrent-challenges=60
    - --v=2
...

$ oc get po -n cert-manager cert-manager-webhook-cfb567bb8-xl25b -o yaml
...
spec:
  containers:
  - args:
    - --dynamic-serving-ca-secret-name=cert-manager-webhook-ca
    - --dynamic-serving-ca-secret-namespace=$(POD_NAMESPACE)
    - --dynamic-serving-dns-names=cert-manager-webhook,cert-manager-webhook.$(POD_NAMESPACE),cert-manager-webhook.$(POD_NAMESPACE).svc
    - --secure-port=10250
    - --v=2
...

1. Pods should be updated and redepolyed automatically after patched arguments "--feature-gates=...".
2. Create a Certificate with "spec.literalSubject" should success.

Upsream doc about feature-gates: https://cert-manager.io/docs/installation/configuring-components/#feature-gates

Checked operator's codebase, found that "--feature-gates" is not a supported Args: https://github.com/openshift/cert-manager-operator/blob/master/pkg/controller/deployment/deployment_overrides_validation.go

There is a workaround by using "unsupportedConfigOverrides": https://github.com/openshift/cert-manager-operator?tab=readme-ov-file#using-unsupported-config-overrides-options