How to disable mat-autocomplete on formBuilder?

I am trying to create a form in which once an option is selected in the first field, this selection gives the options of the second field, which is a mat-autocomplete, also when value from the mat-autocomplete is selected, it is filled with mat-chips.

The problem is that I am not able to make the second field disabled until the first field is filled.

I have tried both different ways, like the indicated by the console warning:

"It looks like you're using the disabled attribute with a reactive form directive. If you set disabled to true
  when you set up this control in your component class, the disabled attribute will actually be set in the DOM for
  you. We recommend using this approach to avoid 'changed after checked' errors.

  Example:
  // Specify the `disabled` property at control creation time:
  form = new FormGroup({
    first: new FormControl({value: 'Nancy', disabled: true}, Validators.required),
    last: new FormControl('Drew', Validators.required)
  });

  // Controls can also be enabled/disabled after creation:
  form.get('first')?.enable();
  form.get('last')?.disable();"

I tried the response of this question too:

Angular mat-autocomplete disable input FormControl not working

But in the end I had to do it like this (that give me the warning):

HTML

<div class="modal-descriptors" [formGroup]="filterValueForm">
    <mat-form-field appearance="outline" class="form-field">
      <mat-label>tag</mat-label>
      <mat-select (selectionChange)="onFilterChange($event)" formControlName="filterSelectCtrl" required>
        <mat-option *ngFor="let filter of filters" [value]="filter.code">{{ filter.code }}</mat-option>
      </mat-select>
    </mat-form-field>

    <mat-form-field appearance="outline" class="modal-descriptors">
      <mat-label>condition</mat-label>
      <mat-select formControlName="filterConditionCtrl" required>
        <mat-option value="true">{{ apply$ | async }}</mat-option>
        <mat-option value="false">{{ notApply$ | async }}</mat-option>
      </mat-select>
    </mat-form-field>

    <mat-form-field appearance="outline" class="descriptors">
      <mat-label>{{ values }}</mat-label>
      <mat-chip-list #toChipList required>
        <mat-chip
          class="descriptors_label"
          *ngFor="let filterValue of selectedFiltersValue"
          [selectable]="selectable"
          [removable]="removable"
          (removed)="removeSelectedFilterValue(filterValue)">
          {{ filterValue.value }}
          <mat-icon class="iconicon" matChipRemove *ngIf="removable">close</mat-icon>
        </mat-chip>
        <input type="text"
          matInput
          #filterValueInput
          formControlName="filterValueCtrl"
          [matAutocomplete]="autoTo"
          [matChipInputFor]="toChipList"
          [matChipInputSeparatorKeyCodes]="separatorKeysCodes"
          [matChipInputAddOnBlur]="addOnBlur"
          (matChipInputTokenEnd)="add($event)"
          [disabled] = "isFilterValueSelected"
          >
      </mat-chip-list>
      <mat-autocomplete  #autoTo="matAutocomplete" (optionSelected)="selected($event)">
        <mat-option *ngFor="let filterValue of filteredValues" [value]="filterValue">{{ filterValue.value }}</mat-option>
      </mat-autocomplete>
    </mat-form-field>

TS

ngOnInit() {
    this.filterValueForm = this.fb.group({
      filterSelectCtrl: [null, Validators.required],
      filterConditionCtrl: [null, Validators.required],
      filterValueCtrl: [{value: '', disabled: true}, Validators.required], /*this object inside array do nothing*/ 
    })
};

get isFilterValueSelected() {
    return !this.filterValueForm.get('filterSelectCtrl').value ? true : false;
  }

Does anyone know what is wrong or knows a better way to do it?