Ouch, okay, that's something we never considered. I'll see if we can add graphics options in the next update. Thank you for your feedback! :D
I actually found the bigger issue:
I experimented a bit with it in Godot and realized there is no FPS limit. Or you have set one, but it does not work on Mac (EDIT: I just noticed you have VSync set to enabled, so it is porpably just a Mac issue for whatever reason). Either way, I for testing purposes set FPS manually to 60 and that already decreased the average powerdraw from 10w to just 4.5w, despite the high resolution! In combination with a reduction of the resolution (When exporting for mac, there is a "high res" option that is enabled by default, I experimented with just disabling that), the game was only drawing 3-3.5w of power. I am talking about system power and 2w is already from the device being on itself, therefore your game is incredibly low on resources, it just seems like 2 minor oversights led to it consuming that much power.
You already mentioned you would try to adress the resolution issue. I hope I don't come of as entitled or anything, though I believe implementing any kind of FPS limit, however you peeps please, would help the game on mobile platforms to draw vastly less energy, as well as possibly avoiding lag on poorly cooled devices.
Best regards, Mika :)