Konami can be such asshats. They did this intentionally: alpha and beta are easier to get and they're only "R". Gamma is unnecessarily made into an "SR" card for no reason other than to mess you around so that you can't easily have a complete set of three.
For some of you who may be discouraged just remember that konami is actually updating this 🔥. There is always that chance that they implement trading or the card scanner feature from previous games. This card being sr is bull 🔥 tho. If they keep this trend up with the upcoming sets I can see this app dying off. Ain't nobody got time to be grinding for some trashy 🔥 collectible set on an app that doesn't even give you full access to the card data base when we all know they easily could.