Can't measure daily floors with Vivoactive 5!

My Vivoactive 4 started malfunctioning (wouldn't easily connect to recharge, having issues with the top button) so I upgraded to a Vivoactive 5 only to find it DOESN'T have an altimeter! This feature has been on smart watches since they were invented - why did Garmin take it off this one? I am 69% completed an elevation challenge and how am I supposed to finish it?