Yes, this is a MacOS app.

Of course the game will run at any framerate. The problem is that it never runs at 120hz unless screen recording is turned on. I can't exactly tell my users to "record your screen for best performance!". The game itself is not very resource intensive, and none of factors in the documentation apply (Low Power Mode, critical thermal state, accessibility settings, etc). What else can I do to get 120fps on iPhone?

I think what else would help would be to get some diagnostic data from Core Animation. I would like to understand why it's not delivering the preferred refresh rate, even though my app is perfectly capable of it. Is there anything I can probe for with Instruments that will tell me this?