How to make Android WIFI connection static and use always mobile internet? I want to use always my mobile internet although I am connected to the wifi network. 
So I want to make my connection static. 

OS: OO 3.1
Phone: Oneplus 2
Related thread: here
From the linked post your WiFi is not good enough, so combining WiFi and mobile data may work

Speedify claims to do this ( not tried by me)


  Combine your Wi-Fi and Mobile Data Connections for Fast Unbreakable Connectivity