if you are a Splunk Partner, you can access Splunk show (https://show.splunk.com/login/?redirect=/) where you can find many demo environments (also ES), but it isn't open to all.
We can't help you with something that can't be done. ES requires a dedicated SH, but Splunk Cloud trial accounts get a single SH. That is why ES is not available in trial accounts.
--- If this reply helps you, Karma would be appreciated.
find a Splunk Partners and see ES with him/her in a PoC.
Otherwise, ask to your Splunk reference People to enable a trial, but it's difficoult, the easiest way is a Splunk Partner, also because it's difficoult to see ES without an initial configuration that requires at least a little knowledge of this solution.
