I would suggest a cash gate upgrade option. I did this once when I was booked on AA marketed (thus AA stock), AY operated, and there is no way to upgrade in advance. Sure, it is a few hundred dollars, but it worth it for me and I used by AA credit card so at least I got some loyalty points for the purchase. The only catch is that it's day of flight option, and it may not be available if it's booked full.