Passing an Object as a function parameter in Typescript

I am working on an Angular component that contains a function. In this function, I need to pass an Object as a function parameter and call this function with the function parameters. It´s been a while since I have been working with Angular and at the type, "any" was the return type to use with functions; nowadays it seems to be "undefined". However, I am not sure on how to write the function call with the corresponding parameters and would appreciate any help and hints. Thanks in advance!

Here´s the component:

import { Component, Input, OnInit } from '@angular/core';

@Component({
  selector: 'app-root', //  eslint-disable-line @angular-eslint/component-selector
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
})
export class AppComponent implements OnInit {

  public interactionID: number=0;
  @Input()
  public userdata!: Object;


  constructor() {
    // Called first time before the ngOnInit()

  }

  public ngOnInit(): void {

  this.NewWorkItem(this.interactionID, this.userdata );
    
  }

  public NewWorkItem(interactionID: unknown, userData: { FirstName: unknown; LastName: unknown }): void  {
    console.log('NewWorkItem call',interactionID,userData);

    const event: Event = new CustomEvent ('wde.newWorkItem', {
      detail: {
        FirstName: userData.FirstName,
        LastName: userData.LastName,
        InteractionID: interactionID
      },
      bubbles: true,
      cancelable: true,
      composed: false,
    });
    console.log('NewWorkItem event',event);  
    window.dispatchEvent(event);

  }
}

This is the function that needs to be called in ngOnInit:

public NewWorkItem(interactionID: unknown, userData: { FirstName: unknown; LastName: unknown }): void  {
    console.log('NewWorkItem call',interactionID,userData);

    const event: Event = new CustomEvent ('wde.newWorkItem', {
      detail: {
        FirstName: userData.FirstName,
        LastName: userData.LastName,
        InteractionID: interactionID
      },
      bubbles: true,
      cancelable: true,
      composed: false,
    });
    console.log('NewWorkItem event',event);  
    window.dispatchEvent(event);

  }

This is the function call in ngOnInit, where I am having the troubles in passing the paramters correctly:

  public ngOnInit(): void {

  this.NewWorkItem(this.interactionID, this.userdata );
    

  }

this.userdata cannot be passed as such as function parameter; the compiler error is:

The argument of Typ "Object" cannot be assigned to the parameter of type "{ FirstName: unknown; LastName: unknown; }"

I was trying to call the function in the ngOnInit method with the corresponding parameters. The error that I get is: The argument of Typ "Object" cannot be assigned to the parameter of type "{ FirstName: unknown; LastName: unknown; }". I cannot tell on how to pass the object as a function parameter correctly.