I have left panel that has form control fields, based on p-dropdown selection , I am updating the right panel content. On page load I am trying to show default values on dropdowns but due to form arrays not updating, the I am not able to see the default values on p-dropdown. Can some please help?

  ngOnInit(): void {
    this.formcopy = this.fb.group({
      scenariotype: [null],
      case: [ null]
    });
    this.getCaseNames();
    this.loadScenarioData(this.scenarioId);
   
  }
  getCaseNames(){
    this.globalparaService.getParam('27e1423a-0d12-1213-b113-aace6639ae08').subscribe((res) => {
      res.data.Case.map(obj => {
        this.caseName.push({ name: obj.CaseName, code: obj.CaseName });
      });
     
    });
  }

  loadScenarioData(scenarioId) {
    this.service.getScenarioByScenarioId(scenarioId).subscribe((res) => {
      this.populateFormdata(res.data);
    });
  }

    populateFormdata(data){
      this.formcopy.patchValue({
      scenariotype: ['Low'],// not updating even though using hardcoded value
      case: [ 'P50']// same here , FE not updating these values
    });



<form [formGroup]="formcopy">
   <p-dropdown [options]="scenario" (onChange)="setScenarioType($event)" optionLabel="name" optionValue="code"
              formControlName="scenariotype" ngDefaultControl ></p-dropdown>

    <p-dropdown [options]="caseName" (onChange)="setCaseName($event)" optionLabel="name" optionValue="code"
            formControlName="case" ngDefaultControl></p-dropdown>
</form>