I see you're using a multi row card, whereas I was using a card, which explains the difference. Looks like that formatting option isn't available for multi row cards. I would recommend creating 6 different cards and set the format individually.
Otherwise, you could create a measure similar to the below:
"=CONCATENATE(TRUNC([value name])/1000000,2),"M")" (for millions)
You'd have to do this for each data point however, so it's not an ideal solution