Still happening on iPhone 14 Pro with iOS 16.4. 🥲 I also tried to disable ProMotion (limit the fps?) in the Settings in iOS, but didn't change anything.

I found a "workaround" for Unity https://forum.unity.com/threads/frame-rate-halves-when-tapping-the-display.1425075/#post-8959434 I am simply "cheating" iOS (I think?) to work like 120 Hz, so when you touch on screen, Frame Rate drops to 60 Hz. But I am setting Application.targetFrameRate to 60. This won't work if you're supporting more than 60 FPS. By the way, didn't test this with non ProMotion iPhones (I'll update this post when I do). And, also, this problem doesn't exist for iPad Pros (with ProMotion), only for iPhones.