Help using google assistant when screen off

Hi, I’m using iplay50 pro.

 

I want to use it for controlling smart devices with google assistant.

 

I’ve settled all settings for using google assistant on screen off but it still doesn’t respond on screen off. It works well on screen on.

 

1. Is it impossible for iplay50 pro?

2. If not, what am I doing wrong?

3. If so, is there any other model on which google assistant works on screen off?

Please provide the system version number of the machine