I am assuming this is about the framerate of the real-time gaze signal, is that correct?

The reason why it is fluctuating in the first place is mostly the way Android is managing resources. The OnePlus 8 phone is in principle capable enough to sustain 200 Hz, but after about a minute Android is automatically reducing the compute resources available to the Companion app in order to save battery, which leads to about 120 Hz remaining. Unfortunately we have no control over this behaviour.

In order to have a fixed framerate, we could limit it to 120 Hz throughout. Would this be helpful? Could you elaborate a bit on why you would you prefer a fixed framerate?