How to get items from a People Picker Feld to my SharePoint List with SPFx/React?

Question

I'm working on a SharePoint Webpart and I use the People Picker Field, to get the names of people to my List. People Picker works fine, i get the name, I can push all my items to my List, except the items from People Picker field. When i enter some name, I get the name on the console in Chrome/EDGE/Firefox, but the Array stays 0. And here ist my #1 problem: [[Prototype]]: Array(0)

Here is my code

import { PeoplePicker } from "@pnp/spfx-controls-react/lib/PeoplePicker"

export default class Test extends React.Component<
ITestProps, 
IPeoplePickerState,

{}
> {

 constructor(props: ITestProps, state: IPeoplePickerState){
    super(props);
    this.addListItem = this.addListItem.bind(this);
    this.getPeoplePicker = this.getPeoplePicker.bind(this);
    this.state = { user:[] };
 }

public render(): React.ReactElement<ITestProps> {
    return (
      <section>
          <div>
            <PeoplePicker context={this.props.context} data-automation-id="addSelectedUsers" placeholder=" Name:" personSelectionLimit={3} ensureUser={true} onChange={this. getPeoplePicker}></PeoplePicker><br></br>
          </div>
        <div>
          <DefaultButton className={styles.btn1} id='btn' onClick={this.addListItem} > Eintragen </DefaultButton>
       </div>
      </section>
    ); 
  }

 public getPeoplePicker(items: any[]){
    console.log('Items:', items);

    let selectedUsers: any[] = [];
    items.map((item) => {
      selectedUsers.push(item.id);
    });
     this.setState({user: selectedUsers});
    
    this.setState({user: selectedUsers});
  
}

public addListItem(): void {
  pnp.sp.web.lists.getByTitle("Test123")
  .items.add({
    'Person': { results: this.state.user },
  })
  .then(i => console.log(i))
  .then(()=> alert("Vielen Dank!"));
}
}

I tried 2 solutions for "getPeoplePicker()", but no one works right.

public getPeoplePicker(items: any[]){
    console.log('Items:', items); 

    let selectedUsers: any[] = [];
    items.map((item) => {
      selectedUsers.push(item.id);
    });
     this.setState({user: selectedUsers});
    
  }

and

public getPeoplePicker(items: any[]){
    console.log('Items:', items); 

    let selectedUsers = [];
    for(let item in items){
       selectedUsers.push(items[item].id);
    }
    this.setState({user: selectedUsers});
    
  }

I get always the same alert.