angular material mat-slide-toggle inside a mat-form-field

You can, however, put a hidden text field inside the mat-form-field to satisfy the requirement and, if necessary, bind all the values together if what you want is to get the same look as the other fields.

<mat-form-field floatLabel="always">
        <mat-label>Label</mat-label>
        <mat-slide-toggle>Raw</mat-slide-toggle>
        <textarea matInput hidden></textarea>
    </mat-form-field>

I present two slightly different hacks with no underline based upon multiple answers

Label above with extended clickable white space, uses css

<mat-form-field floatLabel="always" appearance="none">
  <mat-label>Override Speed</mat-label>
  <mat-slide-toggle [(ngModel)]="Override"><span class="text-invisible">Override Speed</span></mat-slide-toggle>
  <textarea matInput hidden></textarea>
</mat-form-field>

.text-invisible {
  opacity: 0;
}

Label to the right, no css

<mat-form-field floatLabel="always" appearance="none">
  <mat-slide-toggle [(ngModel)]="Override">Override Speed</mat-slide-toggle>
  <textarea matInput hidden></textarea>
</mat-form-field>