Mat expansion panel extend over other html elements

I have a mat expansion panel that I would like to extend over the element below it rather than simply moving that element down. I tried adjust the z-index of the mat-expansion element but that did not work. I haven't seen anything in the angular material docs/github that suggests this can be done. Has anyone done this or know how this could be achieved?

Any help/tips/suggestions would be much appreciated.

UPDATE: my desired solution should look similar to this. It could contain several elements (mat-selection, date picker, etc..)

Big thanks to @wixFitz for getting me going in the right direction but here is the end product.

animation.html:

<div class="report-filter">
  <button 
    mat-raised-button 
    class="filter-button"
    type="button"
    click)="showDiv()"
    ngClass]="{'menu-button-active': filterActive}">
    'TOOLTIP.filter' | translate }}
    <mat-icon>filter_list</mat-icon>
  </button>
  <div [@divState]="divState" class="menu mat-elevation-z8">
    <button
      class="center"
      mat-button
      click)="closeMe()"
      mat-icon-button>
      <mat-icon>close</mat-icon>
    </button>
    <div class="search-brands">
      <mat-form-field>
        <mat-select placeholder="Brands" [(value)]="selectedBrand" panelClass="brandSelectDropdown">
          <mat-option (click)="resetBrand()" value="">none</mat-option>
          <mat-option *ngFor="let brand of brands" (click)="setBrand(brand.brand)" value="brand.brand">{{ brand.brand }}</mat-option>
        </mat-select>
      </mat-form-field>
    </div>
  </div>
</div>

animation.scss:

.report-filter {
  display: flex;
  .filter-button {
    margin: 1rem 0;
  }
}

.menu {
  position: absolute;
  top: 248px;
  right: 23px;
  background-color: $grey600;
  border: 1px solid gray;
  border-radius: 4px;
  z-index: 2;
  .search-brands {
    margin: 2rem 1rem;
    border: 1px solid black;
    background-color: $grey300;
    mat-form-field {
      width: 95%;
      margin: 0rem 0.5rem;
    }
  }
  button {
    mat-icon {
      color: white;
      margin: 0 0 0 0;
    }
  }
}
.menu-button-active {
  background-color: $grey600;
  color: white;
}

animation.ts: In @Component object

animations: [
  trigger('divState', [
    state('show', style({ height: '100vh', width: '20vw' })),
    state('hide', style({ height: '0vh', display: 'none'})),
    transition('show => hide', animate('200ms ease-out')),
    transition('hide => show', animate('300ms ease-in'))
  ])
]

global var

divState: string = "hide";

open and close functions

showDiv() {
  this.divState = (this.divState == 'hide') ? 'show' : 'hide';
  this.filterActive = !this.filterActive
  this.getBrands();
}
  
closeMe() {
  this.divState = 'hide';
  this.filterActive = !this.filterActive
}