Change simple options in android using unity application

Hello there, I want to make my life easier adding some simple options for my phone using unity application.
I need some tips which can help me make functions like:

>choose hours and days (e.g monay, 8:00 - 14:00) and at this time mute my phone (mute multimedia, ringtone and alarm clock), when it's 14:01 unmute my phone

>choose hour (e.g 21:00 - 6:00) and at this time change brightness my phone to the lowest, when it's 6:01 change my phone brightness to half

>this application should work in "background"

 

As far as I know, Unity does not have access to such low-level functionalities. Also, if it does have access, it is way overkill for that.