I have a cheap TCL 4 series that runs google TV. I find the TV and the OS really laggy, I have 3 other TCL tv's that run Roku and they are much better.
I use a CCWGTV as I believe it has superior performance. I would like the TV to turn on automatically to HDMI 1 and not the default home screen. I can not find a setting for this. I am using CEC, so when it works it eventually switches over to HDMI 1 but I am finding it pretty unreliable.
I tried to find a way to do this on my 2015 Bravia. The best I could do was assign the "TV" button on the remote to an HDMI input since I don't use the built-in TV tuner anyway. I use CEC, so the power button on the TV remote turns on my receiver, then I hit that TV button to switch inputs and automatically power-on my Nvidia Shield.
Your model might have something similar in the settings.