Создание массива форм Angular 12

При реализации возникли следующие ошибки:

Error: src/app/expert-cabinet/screens/expert-new-scenario/expert-new-scenario.component.html:47:38 - error TS7052: Element implicitly has an 'any' type because type 'AbstractControl' has no index signature. Did you mean to call 'get'?

<div *ngFor="let question of questionForms.get('questions')['controls']; let i = index" [formGroupName]="i">

Error: src/app/expert-cabinet/screens/expert-new-scenario/expert-new-scenario.component.html:47:38 - error TS2531: Object is possibly 'null'.

<div *ngFor="let question of questionForms.get('questions')['controls']; let i = index" [formGroupName]="i">

Реализован класс:

export class ExpertNewScenarioComponent {

  questionForms: FormGroup;

  constructor() {
    this.questionForms = new FormGroup({
      questions: new FormArray([])
    });

  }
  
  onAddQuestion() {
    const question = new FormGroup({
      name: new FormControl(),
      symptoms: new FormControl()
    });
    (<FormArray>this.questionForms.get('questions')).push(question);
  }

  // Test
  onSaved() {
    console.log(this.questionForms.value);
  }


}

Реализован шаблон:

    <form [formGroup]="questionForms" class="scenario-cards">
      <div formArrayName="questions" class="card scenario-card" >
        <div *ngFor="let question of questionForms.get('questions')['controls']; let i = index" [formGroupName]="i" >
          <div class="mb-3">
            <label for="question-text" class="form-label">Текст вопроса</label>
            <input type="text" class="form-control" id="question-text">
          </div>


          <div class="scenario-card--answer">
            <div class="mb-3">
              <label for="question-answers" class="form-label">Ответы (симптомы)</label>
              <input type="text" class="form-control" id="question-answers">
            </div>

          </div>
        <div class="scenario-btn">
          <button class="btn blue_btn">Удалить вопрос</button>
        </div>
        </div>
      </div>
    </form>

Каким образом возможно решить данные ошибки?