Remember that you're losing out on progress for picking a lower attribute anyway, because raising Dex saves you 25 progress and Sta saves you 20. It will take 20 more progress to reach Dexterity 6, which is going to be a little difficult to obtain at all. So you're losing progress to try to avoid losing progress. Unless you are certain we're going to get something like 45 progress towards Dex before the next Realm without focusing on it specifically, this is counterproductiveI picked Stamina because Dex caps a 6 and raise that pretty quickly we'll end up missing out on progress if we finish it before the next realm.
More importantly...we use Dexterity in many more rolls than we do Stamina. Dexterity would directly and dramatically boost Ling Qi's ability to make targeting her fruitless than Stamina would.