No phone in the market can record video at 120fps even if supported by the hardware. I bought a pixel3 abd was bitten by that fact. The phone will block that capability due to overheating, my only hope us that a developer can unlock the functionality with a custom modification.
Really sucks but that's reality, the phones advertise that speed and its true but only for a few seconds in the slowmo setting not like a dedicated camera that can record hours of video in 120fps, looks like false advertisement to me.
If you have doubt search about it and you will see the rage online!
Oh by the way, I use HedgeCam2, it's based on OpenCam but I like the controls better