Now that cert-manager 1.16 has been released, --set config.enableGatewayAPI=true is the recommended approach for projects that show instructions on how to enable cert-manager's gateway API support, especially on visible projects like Cilium.
Projects that use extraArgs + the deprecated --feature-gates=ExperimentalGatewayAPISupport=true feature flag:
Projects that use extraArgs + --enable-gateway-api instead of config.enableGatewayAPI:
Xref:
fyi @wallrj