This is a notation question not specifically for Dorico. In 3/4 with a quarter note anacrusis, should an empty final measure have a half rest or whole rest? Same in 4/4 with a half note anacrusis?
I think you’ll find different opinions and conventions regarding this; ending with a full bar is probably more common now. But if you do want to end your 3/4 piece with just two beats, you should use two quarter rests, not a half rest.
In addition to @asherber’s answer which I fully agree with please consider:
If the piece / movement contains repeats like a Menuet or Scherzo or another fixed structure like a Rondo I’d recommend the truncated final bar, otherwise the standard empty bar rest.