I got it moved to internal, only by exporting and importing again this json as user anonymous, which comes from a clean artifactory install:

{
    "username" : "anonymous",
    "firstName" : null,
    "lastName" : null,
    "email" : null,
    "realm" : "internal",
    "status" : "enabled",
    "lastLoginTime" : 0,
    "lastLoginIp" : null,
    "password" : null,
    "allowedIps" : [ "*" ],
    "created" : 1738314752329,
    "modified" : 1738314752329,
    "failedLoginAttempts" : 0,
    "statusLastModified" : 1738314752329,
    "passwordLastModified" : 0,
    "customData" : {
      "disabled_password" : {
        "value" : "true",
        "sensitive" : false,
        "clusterLocal" : false
      }
    },
    "groups" : [ ]
  }