Hey janlemon,
Since additional default data is provided in Dataverse, it's possible to get more results in the query than you actually want. If you only want to receive the last name and first name as an object, you can use a "Select" operation. In the From field, you enter the value of the list rows:
outputs('List_rows')?['body/value']
And in Map, you select the fields you want. In your case, you want to get the first name and last name. The mapping could look like this:
{
"firstname": item()['hrapp_firstname'],
"lastname": item()['hrapp_lastname']
}

This way, you'll only get the first name and last name as an object 🙂
I hope this solves your problem.
Greetings,
Aurelius 🙂