I got an alert in the game chat that an error had occurred after a beat a trainer in a gym. I think this happened when it tried to give me money. Afterwards, my player money was set to null which means any time I tried to open a shopkeeper's menu, I immediately fully crash.
It would be fine if this was a one time thing but even after reloading into the game, the error persists and now whenever I rightclick any shop, I immediately crash with the following log.
This seems to also extend to anything else that needs to access my player money. Things like pressing U to open my trainer card also crash my game.