How to get only the latest email record in a case and then set status of that email record (by flow)

How can I get the record only of the latest email in a case and then set the status of that email record to a new value? I have the case record, that's not the problem, but can't get the latest email record and set the status of that email record.

I tried a lot, but didn't succeed. I want to solve this with a flow.

Some screenshots would be helpful for me.

Thanks a lot.

Frank