It looks like you might have Elasticsearch basic version running with Kibana oss version and that is why you can't see index management, can you verify which Kibana package was installed?
The basic license does not expire. I am not sure of way to tell if you have Kibana oss or basic, it just looks like oss from your screenshot. You might be able to install Kibana basic and point your data and config to the new installation, but let me confirm with @tylersmalley if that is the recommended way.
As Liza mentioned, it looks like you have the OSS version of Kibana installed. Where did you obtain the download from? I would recommend obtaining it from our Kibana download page, if you need 7.5.1 specifically you can download that here.
The easiest way to check is to go into the Kibana folder and look at the License.txt. It wont specifically say OSS but it will either say Apache License = OSS or Elastic = basic & paid versions. I know the beats are like this as well. Not sure about the rest of the Elastic tools.
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