With server.insecure, TLS ends at nginx or Envoy and argocd-server serves plain HTTP, which is how Argo CD documents the Gateway API setup. The nginx Ingress now talks HTTP to the http port; the ssl-passthrough annotation did nothing without the controller flag. argocd-folder diffs server-side for the new HTTPRoute.
Required from 3.3, whose ApplicationSet CRD no longer fits the last-applied annotation of client-side apply. Turned on while still on 3.2 so the managed-field migration happens before the CRD grows.
Ruben Hensen