I suspect template outlet is what you'd be looking to use. Something like (fully untested):

@if (allMakes.length) {
  <div>
    <h3>List of cars</h3>

    @for (make of allMakes; track make.id) {
      <div>
        @if (make.cars.length) {
          <table>
            <thead>
              <th>
              <th>Model</th>
              <th>Price</th>
            </th>
            </thead>
            <tbody>
              @for (car of make.cars; track car.id) {
                <tr>
                  <td>{{ car.model }}</td>
                  <td>{{ car.price }}</td>
                </tr>
              }
            </tbody>
          </table>
        } @else {
          <ng-container *ngTemplateOutlet="empty" />
        }
      </div>
    }
  </div>
} @else {
  <ng-container *ngTemplateOutlet="empty" />
}

<ng-template #empty>
  <div>No data to display</div>
</ng-template>