Update: I've found another TCL TV model in the Sofabaton DB that supports the C835 and direct input switch, it was through trial and error until I found the model with supported input switching and the other normal buttons (power etc), unfortunately I didn't pay attention to the model number and there doesn't seem to be a way of seeing it in the App after you've configured the device.

I've found that the Logitech Harmony Beta database has a TestTCL1 TV remote that has the Direct Input codes, i've use my old Harmony Elite remote which works on the TV but the learning function on the X1 hub doesn't learn the codes properly, i've tried multiple times to learn and it detects the codes after a few tries but cannot trigger the code from the X1Hub.