Highest output of SpA is... 273 with a SpA boosting nature. Add in 'Awakened Power' and...546.Not how it works. Huge/Awakened Power double the actual raw number of the stat, not the base stat, so it’s actually more than base 150 SpA. With investment, it’s about the equivalent of fully invested base 200. So yes, Shangrilush will definitely be viable—with a Sp. Atk like that, it’s virtually impossible not to be.
I'm kinda glad this thing has so many counters at the moment