I have a TCL 5 series in my bedroom and I always got the "operation error" on my Pixel 6 but the app works fine on my iPad. Relieved as I'm getting my son a TCL TV for Xmas and I was leaning towards the Roku version because he's familiar with it and it's simple but was contemplating the TCL version with Google TV. So probably not news to anyone but seems to work with different devices
This issue has persisted on and off with three different TCL Roku TVs and multiple Android devices since early 2020.
TV Info from app:
Roku app version
Phone information
I have had the same issue with a Pixel 4, Pixel 5, Samsung Galaxy Tab A8, Galaxy Tab S2, and using Android on a Windows 11 PC. Also, my Samsung Galaxy Chromebook (2020 version, red with 4k screen).
I get the impression it's related to the Android app itself for Roku.
Eventually, it works, but rarely.