I think the proximity sensor being used locks the screen to 60fps for whatever reason because it's under the display. Telegram has the proximity sensor on in chats to enable the "raise to speak" feature where you can raise it to your ear and start recording a voice message.

To enable 120Hz in chats go to:
> Settings
> Chat settings
> Disable "Raise to speak"

Android 12 November security patch is rolling out for Pixels

https://support.google.com/pixelphone/thread/133452459/google-android-pixel-security-update-nov-2021?hl=en

Demonstration of the new feature of "At a Glance" widget.

Source: Kieron Quinn